SlideShare a Scribd company logo
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
CHAPTER
3
Crystal
and
Amorphous Structure
in Materials
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
2
The Space Lattice and Unit Cells
• Atoms, arranged in repetitive 3-Dimensional pattern, in
long range order (LRO) give rise to crystal structure.
• Properties of solids depends upon crystal structure and
bonding force.
• An imaginary network of lines, with atoms at intersection
of lines, representing the arrangement of atoms is called
space lattice.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
Building blocks
3
LEGO block
Unit cell
http://loyalkng.com/2010/03/21/lego-ironman-from-brickshelfs-
legodreams-the-ironman-goes-lego/
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
4
Unit cell
• Unit cell is that block of atoms which repeats itself
to form space lattice.
• Materials arranged in short range order
are called amorphous materials
Unit Cell
Space Lattice
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
5
Crystal Systems and Bravais Lattice
• Only seven different types of unit cells are
necessary to create all point lattices.
• According to Bravais (1811-1863) fourteen
standard unit cells can describe all possible
lattice networks.
• The four basic types of unit cells are
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
6
Types of Unit Cells
• Cubic Unit Cell
• Tetragonal
Simple Body Centered
Face centered
Simple Body Centered
Figure 3.2
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
7
Types of Unit Cells (Cont..)
• Orthorhombic
≠ b ≠ c
• Rhombohedral
Simple Base Centered
Face Centered
Body Centered
Simple
Figure 3.2
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
8
Types of Unit Cells (Cont..)
• Hexagonal
• Monoclinic
• Triclinic
Simple
Simple
Simple
Base
Centered
Figure 3.2
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
9
Principal Metallic Crystal Structures
• 90% of the metals have either Body Centered Cubic
(BCC), Face Centered Cubic (FCC) or Hexagonal Close
Packed (HCP) crystal structure.
• HCP is denser version of simple hexagonal crystal
structure.
BCC Structure FCC Structure HCP Structure
Figure 3.3
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
10
Body Centered Cubic (BCC) Crystal Structure
• Represented as one atom at each corner of cube and one at
the center of cube.
• Each atom has 8 nearest neighbors.
• Therefore, coordination number is 8.
• Examples :-
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
11
BCC Crystal Structure (Cont..)
• Each unit cell has eight 1/8
atom at corners and 1
full atom at the center.
• Therefore each unit cell has
• Atoms contact each
other at cube diagonal
(8x1/8 ) + 1 = 2 atoms
3
4RTherefore, a =
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
12
Atomic Packing Factor of BCC Structure
Atomic Packing Factor =
Volume of atoms in unit cell
Volume of unit cell
Vatoms = = 8.373R3
3
3
4
= 12.32 R3
Therefore APF = 8.723 R
3
12.32 R3 = 0.68
V unit cell = a3 =
3
4
.2
3R
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
13
Face Centered Cubic (FCC) Crystal Structure
• FCC structure is represented as one atom each at the
corner of cube and at the center of each cube face.
• Coordination number for FCC structure is 12
• Atomic Packing Factor is 0.74
• Examples :-
old (a = 0.408)
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
14
FCC Crystal Structure (Cont..)
• Each unit cell has eight 1/8
atom at corners and six ½
atoms at the center of six
faces.
• Therefore each unit cell has
• Atoms contact each other
across cubic face diagonal
(8 x 1/8)+ (6 x ½) = 4 atoms
2
4RTherefore, lattice
constant a =
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
15
Hexagonal Close-Packed Structure
• The HCP structure is represented as an atom at each of 12
corners of a hexagonal prism, 2 atoms at top and bottom
face and 3 atoms in between top and bottom face.
• Atoms attain higher APF by attaining HCP structure than
simple hexagonal structure.
• The coordination number is 12, APF = 0.74.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
16
HCP Crystal Structure (Cont..)
• Each atom has six 1/6 atoms at each of top and bottom
layer, two half atoms at top and bottom layer and 3 full
atoms at the middle layer.
• Therefore each HCP unit cell has
• Examples:-
• Ideal c/a ratio is 1.633.
(2 x 6 x 1/6) + (2 x ½) + 3 = 6 atoms
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
YouTube videos links
• http://www.youtube.com/watch?v=Rm-
i1c7zr6Q
• http://www.youtube.com/watch?v=F4Du
4zI4GJ0
• http://www.youtube.com/watch?v=vYky
UqUa6vU
• http://www.youtube.com/watch?v=NYV
SI83KiKU
17
http://www.youtube.com/watch?v=Rm-i1c7zr6Q
http://www.youtube.com/watch?v=F4Du4zI4GJ0
http://www.youtube.com/watch?v=vYkyUqUa6vU
http://www.youtube.com/watch?v=NYVSI83KiKU
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
18
Atom Positions in Cubic Unit Cells
• Cartesian coordinate system is use to locate atoms.
• In a cubic unit cell
posite of positive directions.
• Atom positions are
located using unit
distances along the
axes.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
19
Directions in Cubic Unit Cells
• In cubic crystals, Direction Indices are vector components
of directions resolved along each axes, resolved to smallest
integers.
• Direction indices are position coordinates of unit cell
where the direction vector emerges from cell surface,
converted to integers.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
20
Procedure to Find Direction Indices
(0,0,0)
(1,1/2,1)
z
Produce the direction vector till it
emerges from surface of cubic cell
Determine the coordinates of point
of emergence and origin
Subtract coordinates of point of
Emergence by that of origin
(1,1/2,1) - (0,0,0)
= (1,1/2,1)
Are all are
integers?
Convert them to
smallest possible
integer by multiplying
by an integer.
2 x (1,1/2,1)
= (2,1,2)
Are any of the direction
vectors negative?
Represent the indices in a square
bracket without comas with a
over negative index (Eg: [121])
Represent the indices in a square
bracket without comas (Eg: [212] )
The direction indices are [212]
x
y
YES
NO
YES
NO
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
21
Direction Indices - Example
• Determine direction indices of the given vector.
Origin coordinates are (3/4 , 0 , 1/4).
Emergence coordinates are (1/4, 1/2, 1/2).
Subtracting origin coordinates
from emergence coordinates,
(3/4 , 0 , 1/4) - (1/4, 1/2, 1/2)
= (-1/2, 1/2, 1/4)
Multiply by 4 to convert all
fractions to integers
4 x (-1/2, 1/2, 1/4) = (-2, 2, 1)
Therefore, the direction indices are [ 2 2 1 ]
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
22
Miller Indices
• Miller Indices are are used to refer to specific lattice
planes of atoms.
• They are reciprocals of the fractional intercepts (with
fractions cleared) that the plane makes with the
crystallographic x,y and z axes of three nonparallel edges
of the cubic unit cell.
z
x
y
Miller Indices =(111)
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
23
Miller Indices - Procedure
Choose a plane that does not pass
through origin
Determine the x,y and z intercepts
of the plane
Find the reciprocals of the intercepts
Fractions?
Clear fractions by
multiplying by an integer
to determine smallest set
of whole numbers
Enclose in parenthesis (hkl)where h,k,l
are miller indicesof cubic crystal plane
forx,y and z axes. Eg: (111)
Place a ‘bar’ over the
Negative indices
Yes
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
Miller Indices - Examples
• Intercepts of the plane at x,y
& z axes are 1, ∞ and ∞
• Taking reciprocals we get
(1,0,0).
• Miller indices are (100).
*******************
• Intercepts are 1/3, 2/3 & 1.
• taking reciprocals we get (3,
3/2, 1).
• Multiplying by 2 to clear
fractions, we get (6,3,2).
• Miller indices are (632).
x
x
y
z
(100)
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
Miller Indices - Examples
• Plot the plane (101)
Taking reciprocals of the indices
we get (1 ∞ 1).
The intercepts of the plane are
x=1, y= ∞ (parallel to y) and z=1.
******************************
• Plot the plane (2 2 1)
Taking reciprocals of the indices
we get (1/2 1/2 1).
The intercepts of the plane are
x=1/2, y= 1/2 and z=1.
Figure EP3.7 a
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
26
Miller Indices - Example
• Plot the plane (110)
The reciprocals are (1,-1, ∞)
The intercepts are x=1, y=-1 and z= ∞ (parallel to z axis)
To show this plane in a
single unit cell, the
origin is moved along
the positive direction
of y axis by 1 unit.
x
y
z(110)
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
27
Miller Indices – Important Relationship
• Direction indices of a direction perpendicular to a crystal
plane are same as miller indices of the plane.
• Example:-
• Interplanar spacing between parallel closest planes with
same miller indices is given by
lkh
d
a
hkl 222
++
=
Figure EP3.7b
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
28
Planes and Directions in Hexagonal Unit Cells
• Four indices are used (hkil) called as Miller-
Bravais indices.
• Four axes are used (a1, a2, a3 and c).
• Reciprocal of the intercepts that a crystal
plane makes with the a1, a2, a3 and c axes give
the h,k,I and l indices respectively.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
29
Hexagonal Unit Cell - Examples
• Basal Planes:-
Intercepts a1 = ∞
a2 = ∞
a3 = ∞
c = 1
(hkli) = (0001)
• Prism Planes :-
For plane ABCD,
Intercepts a1 = 1
a2 = ∞
a3 = -1
c = ∞
(hkli) = (1010)
Figure 3.17 a&b
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
30
Directions in HCP Unit Cells
• Indicated by 4 indices [uvtw].
• u,v,t and w are lattice vectors in a1, a2, a3 and c directions
respectively.
• Example:-
For a1, a2, a3 directions, the direction indices are
[ 2 1 1 0], [1 2 1 0] and [ 1 1 2 0] respectively.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
31
Comparison of FCC and HCP crystals
• Both FCC and HCP are close packed and have
APF 0.74.
• FCC crystal is close packed in (111) plane while
HCP is close packed in (0001) plane.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
32
Structural Difference between HCP and FCC
Consider a layer
of atoms (Plane ‘A’)
Another layer (plane ‘B’)
of atoms is placed in ‘a’
Void of plane ‘A’
Third layer of Atoms placed
in ‘b’ Voids of plane ‘B’. (Identical
to plane ‘A’.) HCP crystal.
Third layer of Atoms placed
in ‘a’ voids of plane ‘B’. Resulting
In 3rd Plane C. FCC crystal.
Plane A
‘a’ void
‘b’ void
Plane A
Plane B
‘a’ void
‘b’ void
Plane A
Plane B
Plane A
Plane A
Plane B
Plane C
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
33
Volume Density
• Volume density of metal =
• Example:- Copper (FCC) has atomic mass of 63.54 g/mol
and atomic radius of 0.1278 nm.
vρ Mass/Unit cellVolume/Unit cell=
a=
2
4R =
2
1278.04 nm×
= 0.361 nm
Volume of unit cell = V= a3 = (0.361nm)3 = 4.7 x 10-29 m3
vρ
FCC unit cell has 4 atoms.
Mass of unit cell = m =
×
−
g
Mg
molatmos
molgatoms 6
23
10
/107.4
)/54.63)(4(
= 4.22 x 10-28 Mg
33329
28
98.898.8
107.4
1022.4
cm
g
m
Mg
m
Mg
V
m
==
×
×
==
−
−
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
34
Planar Atomic Density
• Planar atomic density=
• Example:- In Iron (BCC, a=0.287), The (100) plane
intersects center of 5 atoms (Four ¼ and 1 full atom).
Area of 110 plane =
ρ
p=
Equivalent number of atoms whose
centers are intersected by selected area
Selected area
222 aaa =×
ρ
p ( )2287.02
2
=
2
13
2
1072.12.17
mmnm
atoms ×
==
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
35
Linear Atomic Density
• Linear atomic density =
• Example:- For a FCC copper crystal (a=0.361), the [110]
direction intersects 2 half diameters and 1 full diameter.
Length of line =
ρ
l
=
Number of atomic diameters
intersected by selected length
of line in direction of interest
Selected length of line
mm
atoms
nm
atoms
nm
atoms 61092.392.3
361.02
2 ×
==
×
=ρ
l
nm361.02 ×
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
36
Polymorphism or Allotropy
• Metals exist in more than one crystalline form. This is
caller polymorphism or allotropy.
• Temperature and pressure leads to change in crystalline
forms.
• Example:- Iron exists in both BCC and FCC form
depending on the temperature.
-2730C 9120C 13940C 15390C
α Iron
BCC
γ Iron
FCC
δ Iron
BCC
Liquid
Iron
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
37
Crystal Structure Analysis
• Information about crystal structure are obtained using X-
Rays.
• The X-rays used are about the same wavelength (0.05-
0.25 nm) as distance between crystal lattice planes.
35 KV
(Eg:
Molybdenum)
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
X-Ray Spectrum of Molybdenum
• X-Ray spectrum of Molybdenum is
obtained when Molybdenum is used
as target metal.
• Kα and Kβ are characteristic of an
element.
• For Molybdenum Kα occurs at
wave length of about 0.07nm.
• Electrons of n=1 shell of target
metal are knocked out by
bombarding electrons.
• Electrons of higher level drop
down by releasing energy to replace
lost electrons
48
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
39
X-Ray Diffraction
• Crystal planes of target metal act as mirrors reflecting X-
ray beam.
• If rays leaving a set of planes
are out of phase (as in case of
arbitrary angle of incidence)
no reinforced beam is
produced.
• If rays leaving are in phase,
reinforced beams are
produced.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
40
X-Ray Diffraction (Cont..)
• For rays reflected from different planes to be in phase, the
extra distance traveled by a ray should be a integral
multiple of wave length λ .
nλ = MP + PN (n = 1,2…)
n is order of diffraction
If dhkl is interplanar distance,
Then MP = PN = dhkl.Sinθ
Therefore, λ = 2 dhkl.Sinθ
After A.G. Guy and J.J. Hren, “Elements of Physical
Metallurgy,” 3d ed., Addison-Wesley, 1974, p.201.)
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
41
Interpreting Diffraction Data
• We know that
2
2222
2
222
222
4
2
2
a
lkh
Sin
lkh
aSin
dSin
lkh
a
d hkl
++
=
++
=
=
++
=
λ
θ
θ
λ
θλSince
Note that the wavelength λ and lattice constant a are the same
For both incoming and outgoing radiation.
Substituting for d,
Therefore
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
42
Interpreting Diffraction Data (Cont..)
• For planes ‘A’ and ‘B’ we get two equations
2
2222
2
2
2222
2
4
)(
4
)(
a
lkh
Sin
a
lkh
Sin
BBB
B
AAA
A
++
=
++
=
λ
θ
λ
θ (For plane ‘A’)
(For plane ‘B’)
Dividing each other, we get
)(
)(
222
222
2
2
BBB
AAA
B
A
lkh
lkh
Sin
Sin
++
++
=
θ
θ
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
43
X-Ray Diffraction Analysis
• Powdered specimen is used for X-ray diffraction analysis as
the
random orientation facilitates different angle of incidence.
• Radiation counter detects angle and intensity of diffracted
beam.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
44
Diffraction Condition for Cubic Cells
• For BCC structure, diffraction occurs only on planes
whose miller indices when added together total to an even
number.
I.e. (h+k+l) = even Reflections present
(h+k+l) = odd Reflections absent
• For FCC structure, diffraction occurs only on planes
whose miller indices are either all even or all odd.
I.e. (h,k,l) all even Reflections present
(h,k,l) all odd Reflections present
(h,k,l) not all even or all odd Reflections absent.
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
45
Interpreting Experimental Data
• For BCC crystals, the first two sets of diffracting planes
are {110} and {200} planes.
Therefore
• For FCC crystals the first two sets of diffracting planes are
{111} and {200} planes
Therefore
5.0
)002(
)011(
222
222
2
2
=
++
++
=
B
A
Sin
Sin
θ
θ
75.0
)002(
)111(
222
222
2
2
=
++
++
=
B
A
Sin
Sin
θ
θ
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
46
Crystal Structure of Unknown Metal
Unknown
metal
Crystallographic
Analysis
FCC
Crystal
Structure
BCC
Crystal
Structure
75.02
2
=
B
A
Sin
Sin
θ
θ 5.0
2
2
=
B
A
Sin
Sin
θ
θ
Foundations of Materials Science and Engineering, 5th Edn.
Smith and Hashemi
Copyright © The McGraw-Hill Companies, Inc. Permission
required for reproduction or display
47
Amorphous Materials
• Random spatial positions of atoms
• Polymers: Secondary bonds do not allow
formation of parallel and tightly packed chains
during solidification.
micrystalline.
• Glass is a ceramic made up of SiO4 4- tetrahedron
subunits – limited mobility.
• Rapid cooling of metals (10 8 K/s) can give rise to
amorphous structure (metallic glass).
• Metallic glass has superior metallic properties.
Definitions
• Crystal structure: the manner in which atoms, ions and
molecules are spatially arranged
• Lattice: a three dimensional array of points coinciding with
atom positions
• Allotropy: a property of an element to coexist in more than
one crystal structure
• Amorphous materials: materials like glasses that have no long
range order or crystal structure
• Isotropic: having same properties in all directions
• Anisotropic: property of materials that have different
properties in different directions
• Unit cell: subdivision of a crystal structure into small repeat
entities
• Basis or motif: a group of atoms associated with a lattice point
• Coordination number: number of nearest neighbors of an atom
in a crystal structure
• Atomic packing fraction: fraction of plane, volume or
direction that is actually occupied by atoms
• Lattice parameter: the unit cell edge lengths and angle
between them
• Closed packed directions: directions in a crystal lattice along
which atoms are in contact
Definitions
• Cubic site: an interstitial site with coordination number of
eight
• Tetrahedral site: an interstitial site with coordination number
of four
• Octahedral site: an interstitial site with coordination number
of six
• Bravais lattice: fourteen possible lattice arrangements that are
possible using lattice points in 3D
space
• Miller indices: a notation used to describe specific
crystallographic planes and directions
• Miller indices of directions: are vector components of the
directions resolved along each of the
coordinate axes
• Miller indices of planes: are defined as reciprocals of
fractional intercepts that the planes makes
with coordinate axes
• Metallic glass: metals with an amorphous atomic structure
• Linear atomic density: the number of lattice points per unit
length along a direction
• Planar density: the number of atoms whose centers are
intersected by the plane per unit area
• Volume density: the ratio of mass per unit volume of a unit
cell
Ch03-revised-D2LCHAPTER �3The Space Lattice and Unit
CellsBuilding blocksUnit cellCrystal Systems and Bravais
LatticeTypes of Unit CellsTypes of Unit Cells (Cont..)Types of
Unit Cells (Cont..)Principal Metallic Crystal Structures Body
Centered Cubic (BCC) Crystal StructureBCC Crystal Structure
(Cont..)Atomic Packing Factor of BCC Structure Face Centered
Cubic (FCC) Crystal StructureFCC Crystal Structure
(Cont..)Hexagonal Close-Packed StructureHCP Crystal
Structure (Cont..)YouTube videos linksAtom Positions in Cubic
Unit CellsDirections in Cubic Unit CellsProcedure to Find
Direction IndicesDirection Indices - ExampleMiller
IndicesMiller Indices - ProcedureMiller Indices -
ExamplesMiller Indices - ExamplesMiller Indices -
ExampleMiller Indices – Important RelationshipPlanes and
Directions in Hexagonal Unit Cells Hexagonal Unit Cell -
ExamplesDirections in HCP Unit CellsComparison of FCC and
HCP crystalsStructural Difference between HCP and
FCCVolume DensityPlanar Atomic DensityLinear Atomic
DensityPolymorphism or AllotropyCrystal Structure AnalysisX-
Ray Spectrum of MolybdenumX-Ray DiffractionX-Ray
Diffraction (Cont..)Interpreting Diffraction DataInterpreting
Diffraction Data (Cont..)X-Ray Diffraction AnalysisDiffraction
Condition for Cubic CellsInterpreting Experimental DataCrystal
Structure of Unknown MetalAmorphous MaterialsDefinitions-
ch-3DefinitionsDefinitions
ENGR 1210 HW 3
1
Homework 3 on chapter 3; (Total points: 100)
Reading assignments: Chapter 3 from textbook, notes and slides
Student Name: _______________________________ MTSU ID:
____________________
Honor pledge: I _______________________________
acknowledge that I have neither received
nor given any unauthorized help/aid during this assignment.
Part 1 Key Engineering Terms: fill in the blanks – 25 points
1. Crystal structure: The manner in which atoms, ions and
molecules are
_____________________________________ arranged.
2. Lattice: A three dimensional array of points coinciding with
________________________________ positions.
3. Unit cell: A ____________________ of lattice into small
_________________________
entities still retaining overall characteristics of the entire
lattice.
4. Basis or motif: a group of atoms associated with
_____________________________.
5. Crystalline material: A crystalline material is one in which
the atoms are situated in a
_____________________________________ or periodic array
over
________________________________ atomic distances.
6. Coordination number: number of
________________________________ neighbors of an
atom in a crystal structure.
7. Lattice parameter: The unit cell
___________________________ and the
_________________________ between the edges.
8. Closed packed direction: direction in a crystal lattice along
which atoms are in
_________________________________.
2
9. Bravais lattices: _______________________________
possible lattices arrangements
using lattice points in 3 dimensional space.
10. Atomic packing fraction: a fraction of a plane, volume or
direction that is
_____________________________ occupied with atoms.
11. Allotropy or Polymorphism: a property of an element to
coexist in more than
________________________________ crystal structures.
12. Amorphous Materials: Materials including glasses that have
______________________________ long range order or crystal
structure.
13. Isotropic: Having _________________________________
properties in all directions.
14. Anisotropic: Having
_________________________________ properties in different
directions.
15. Miller Indices of Directions: Are
_____________________________ components of the
directions resolved along each of the coordinate axes.
16. Miller Indices of Planes: Are
_____________________________ of fractional
_________________________________ that plane makes with
coordinate axes.
17. Linear density: It is defined as the number of lattice points
or atomic diameters per unit
____________________________________ of the direction.
18. Planar density: The number of atoms whose
________________________________ are
intersected by the plane per unit
_____________________________.
19. X-ray diffraction: A technique to analyze the
_____________________________ of
materials using a beam of X-rays as source.
20. Metallic glass: Metals with
____________________________ crystal structure.
3
Part 2 Learning concepts/reflections/problems – 65 points
1. Sketch the unit cells of Simple Cubic, Body Centered Cubic
and Face Centered Cubic
lattices and determine and show calculations for following:
A. Number of atoms per unit cell
B. Equation/relation for radius and lattice parameter (unit cell
edge length)
C. Atomic Packing Fraction (APF) 15 points
2. Calculate the radius of a palladium (Pd) atom, given that Pd
has an FCC crystal structure,
a density of 12.0 g/cm3, and an atomic weight of 106.4 g/mol.
Assume Avogadro’s
number = 6.022 x 1023 atoms/mol 5 points
3. Determine the Miller Indices of directions A, B, C and D as
shown in figure below:
10 points
4
4. Determine Miller Indices of planes as shown in figure below:
10 points
5. Determine Miller Bravais Indices [hkil] of directions as
shown in figure below:
10 points
5
6. Determine Miller Bravais Indices (hkil) of planes as shown in
figure below:
10 points
7. Define diffraction. Write an expression for Bragg’s law of
diffraction and explain the
terms of the equation. 5 points
Part 3 Materials design – 10 points
1. Why metallic crystal structure are dense? Explain. 5 points
2. Give 2 materials examples of each of the following crystal
structures:
a. Simple cubic (SC)
b. Body Centered Cubuc (BCC)
c. Face Centered Cubic (FCC)
d. Hexagonal Closed Packed (HCP) 5 points
6
Bonus questions:
1. Explain why the properties of polycrystalline materials are
most often isotropic?
5 points
2. Explain two differences between an optical microscope and a
scanning electron
microscope (SEM). 5 points
3. Calculate theoretical density of Chromium which has Body
Centered Cubic structure and
atomic weight of 52 g/mol and atomic radius of 0.125 nm.
Assume Avogadro’s number =
6.022 x 1023 atoms/mol 5 points
Note: Please use extra sheets wherever necessary to answer the
questions. All HW must be
uploaded via D2L Dropbox system. Students are highly
encouraged to refer textbook, notes
and slides.

More Related Content

Similar to Foundations of Materials Science and Engineering, 5th Edn. Sm.docx

1676375195643 civil mechPPT Unit-IV.pptx
1676375195643  civil mechPPT Unit-IV.pptx1676375195643  civil mechPPT Unit-IV.pptx
1676375195643 civil mechPPT Unit-IV.pptx
AjayprasathN
 
Crystal Structure.ppt
Crystal Structure.pptCrystal Structure.ppt
Crystal Structure.ppt
yishChaudhari
 
New ppt.pptx .
New ppt.pptx                                   .New ppt.pptx                                   .
New ppt.pptx .
happycocoman
 
Crystal structures
Crystal structuresCrystal structures
Crystal structures
Ratnadeepsinh Jadeja
 
4353486.ppt
4353486.ppt4353486.ppt
4353486.ppt
Nadyshuka
 
Crystallography
CrystallographyCrystallography
Crystal structures in material science
Crystal structures in material scienceCrystal structures in material science
Crystal structures in material science
Sachin Hariprasad
 
Ic technology- Crystal structure and Crystal growth
Ic technology- Crystal structure and Crystal growthIc technology- Crystal structure and Crystal growth
Ic technology- Crystal structure and Crystal growth
kriticka sharma
 
Crystalography
CrystalographyCrystalography
Crystalography
Anshul Chauhan
 
Chapter 3-Crystal Structure ceramic .pdf
Chapter 3-Crystal Structure ceramic .pdfChapter 3-Crystal Structure ceramic .pdf
Chapter 3-Crystal Structure ceramic .pdf
7zarlamin1
 
Classwork 4 crystal_structures[1]
Classwork 4 crystal_structures[1]Classwork 4 crystal_structures[1]
Classwork 4 crystal_structures[1]
Hera Rahmaliani
 
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.pptWeek-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
GERONVENICEV
 
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.pptWeek-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
Nadyshuka
 
Materials_Ch3.pdf
Materials_Ch3.pdfMaterials_Ch3.pdf
Materials_Ch3.pdf
sabry said
 
Crystal structure.pdf
Crystal structure.pdfCrystal structure.pdf
Crystal structure.pdf
AkshatMehrotra14
 
Lecture 2-Crystal Structure.pptx
Lecture 2-Crystal Structure.pptxLecture 2-Crystal Structure.pptx
Lecture 2-Crystal Structure.pptx
Hdjd9
 
Videos lecture for b.tech ! Edhole
Videos lecture for b.tech ! EdholeVideos lecture for b.tech ! Edhole
Videos lecture for b.tech ! Edhole
Edhole.com
 
Crystal and Crystal Systems PowerPoint Presentation
Crystal and Crystal Systems PowerPoint PresentationCrystal and Crystal Systems PowerPoint Presentation
Crystal and Crystal Systems PowerPoint Presentation
MuhammadUsman1795
 

Similar to Foundations of Materials Science and Engineering, 5th Edn. Sm.docx (20)

1676375195643 civil mechPPT Unit-IV.pptx
1676375195643  civil mechPPT Unit-IV.pptx1676375195643  civil mechPPT Unit-IV.pptx
1676375195643 civil mechPPT Unit-IV.pptx
 
Crystal Structure.ppt
Crystal Structure.pptCrystal Structure.ppt
Crystal Structure.ppt
 
New ppt.pptx .
New ppt.pptx                                   .New ppt.pptx                                   .
New ppt.pptx .
 
Crystal structures
Crystal structuresCrystal structures
Crystal structures
 
4353486.ppt
4353486.ppt4353486.ppt
4353486.ppt
 
Crystallography
CrystallographyCrystallography
Crystallography
 
Crystal structures in material science
Crystal structures in material scienceCrystal structures in material science
Crystal structures in material science
 
Ic technology- Crystal structure and Crystal growth
Ic technology- Crystal structure and Crystal growthIc technology- Crystal structure and Crystal growth
Ic technology- Crystal structure and Crystal growth
 
Crystalography
CrystalographyCrystalography
Crystalography
 
Chapter 3-Crystal Structure ceramic .pdf
Chapter 3-Crystal Structure ceramic .pdfChapter 3-Crystal Structure ceramic .pdf
Chapter 3-Crystal Structure ceramic .pdf
 
Classwork 4 crystal_structures[1]
Classwork 4 crystal_structures[1]Classwork 4 crystal_structures[1]
Classwork 4 crystal_structures[1]
 
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.pptWeek-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
 
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.pptWeek-3-Day-1-Structure-of-Crystalline-Solids.ppt
Week-3-Day-1-Structure-of-Crystalline-Solids.ppt
 
Phy351 ch 3
Phy351 ch 3Phy351 ch 3
Phy351 ch 3
 
Phy351 ch 3
Phy351 ch 3Phy351 ch 3
Phy351 ch 3
 
Materials_Ch3.pdf
Materials_Ch3.pdfMaterials_Ch3.pdf
Materials_Ch3.pdf
 
Crystal structure.pdf
Crystal structure.pdfCrystal structure.pdf
Crystal structure.pdf
 
Lecture 2-Crystal Structure.pptx
Lecture 2-Crystal Structure.pptxLecture 2-Crystal Structure.pptx
Lecture 2-Crystal Structure.pptx
 
Videos lecture for b.tech ! Edhole
Videos lecture for b.tech ! EdholeVideos lecture for b.tech ! Edhole
Videos lecture for b.tech ! Edhole
 
Crystal and Crystal Systems PowerPoint Presentation
Crystal and Crystal Systems PowerPoint PresentationCrystal and Crystal Systems PowerPoint Presentation
Crystal and Crystal Systems PowerPoint Presentation
 

More from hanneloremccaffery

 Explain how firms can benefit from forecastingexchange rates .docx
 Explain how firms can benefit from forecastingexchange rates .docx Explain how firms can benefit from forecastingexchange rates .docx
 Explain how firms can benefit from forecastingexchange rates .docx
hanneloremccaffery
 
•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx
•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx
•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx
hanneloremccaffery
 
•No less than 4 pages causal argument researched essay •In.docx
•No less than 4 pages causal argument researched essay •In.docx•No less than 4 pages causal argument researched essay •In.docx
•No less than 4 pages causal argument researched essay •In.docx
hanneloremccaffery
 
•Focus on two or three things in the Mesopotamian andor Ovids ac.docx
•Focus on two or three things in the Mesopotamian andor Ovids ac.docx•Focus on two or three things in the Mesopotamian andor Ovids ac.docx
•Focus on two or three things in the Mesopotamian andor Ovids ac.docx
hanneloremccaffery
 
•Langbein, L. (2012). Public program evaluation A statistical guide.docx
•Langbein, L. (2012). Public program evaluation A statistical guide.docx•Langbein, L. (2012). Public program evaluation A statistical guide.docx
•Langbein, L. (2012). Public program evaluation A statistical guide.docx
hanneloremccaffery
 
•Chapter 10 Do you think it is possible for an outsider to accura.docx
•Chapter 10 Do you think it is possible for an outsider to accura.docx•Chapter 10 Do you think it is possible for an outsider to accura.docx
•Chapter 10 Do you think it is possible for an outsider to accura.docx
hanneloremccaffery
 
·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx
·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx
·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx
hanneloremccaffery
 
·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx
·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx
·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx
hanneloremccaffery
 
·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx
·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx
·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx
hanneloremccaffery
 
[Type here]Ok. This school makes me confused. The summary of t.docx
[Type here]Ok. This school makes me confused. The summary of t.docx[Type here]Ok. This school makes me confused. The summary of t.docx
[Type here]Ok. This school makes me confused. The summary of t.docx
hanneloremccaffery
 
© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx
© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx
© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx
hanneloremccaffery
 
© 2016 Laureate Education, Inc. Page 1 of 3 RWRCOEL Prof.docx
© 2016 Laureate Education, Inc.   Page 1 of 3 RWRCOEL Prof.docx© 2016 Laureate Education, Inc.   Page 1 of 3 RWRCOEL Prof.docx
© 2016 Laureate Education, Inc. Page 1 of 3 RWRCOEL Prof.docx
hanneloremccaffery
 
© 2022 Post University, ALL RIGHTS RESERVED Due Date.docx
© 2022 Post University, ALL RIGHTS RESERVED  Due Date.docx© 2022 Post University, ALL RIGHTS RESERVED  Due Date.docx
© 2022 Post University, ALL RIGHTS RESERVED Due Date.docx
hanneloremccaffery
 
{DiscriminationGENERAL DISCRIMINATI.docx
{DiscriminationGENERAL DISCRIMINATI.docx{DiscriminationGENERAL DISCRIMINATI.docx
{DiscriminationGENERAL DISCRIMINATI.docx
hanneloremccaffery
 
~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx
~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx
~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx
hanneloremccaffery
 
© 2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx
©  2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx©  2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx
© 2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx
hanneloremccaffery
 
`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx
`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx
`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx
hanneloremccaffery
 
^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx
^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx
^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx
hanneloremccaffery
 
`Inclusiveness. The main.docx
`Inclusiveness. The main.docx`Inclusiveness. The main.docx
`Inclusiveness. The main.docx
hanneloremccaffery
 
__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx
__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx
__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx
hanneloremccaffery
 

More from hanneloremccaffery (20)

 Explain how firms can benefit from forecastingexchange rates .docx
 Explain how firms can benefit from forecastingexchange rates .docx Explain how firms can benefit from forecastingexchange rates .docx
 Explain how firms can benefit from forecastingexchange rates .docx
 
•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx
•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx
•POL201 •Discussions •Week 5 - DiscussionVoter and Voter Tu.docx
 
•No less than 4 pages causal argument researched essay •In.docx
•No less than 4 pages causal argument researched essay •In.docx•No less than 4 pages causal argument researched essay •In.docx
•No less than 4 pages causal argument researched essay •In.docx
 
•Focus on two or three things in the Mesopotamian andor Ovids ac.docx
•Focus on two or three things in the Mesopotamian andor Ovids ac.docx•Focus on two or three things in the Mesopotamian andor Ovids ac.docx
•Focus on two or three things in the Mesopotamian andor Ovids ac.docx
 
•Langbein, L. (2012). Public program evaluation A statistical guide.docx
•Langbein, L. (2012). Public program evaluation A statistical guide.docx•Langbein, L. (2012). Public program evaluation A statistical guide.docx
•Langbein, L. (2012). Public program evaluation A statistical guide.docx
 
•Chapter 10 Do you think it is possible for an outsider to accura.docx
•Chapter 10 Do you think it is possible for an outsider to accura.docx•Chapter 10 Do you think it is possible for an outsider to accura.docx
•Chapter 10 Do you think it is possible for an outsider to accura.docx
 
·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx
·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx
·         Bakit Di gaanong kaganda ang pagturo sa UST sa panahon.docx
 
·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx
·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx
·YOUR INDIVIDUAL PAPER IS ARGUMENTATIVE OR POSITIONAL(Heal.docx
 
·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx
·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx
·Write a 750- to 1,Write a 750- to 1,200-word paper that.docx
 
[Type here]Ok. This school makes me confused. The summary of t.docx
[Type here]Ok. This school makes me confused. The summary of t.docx[Type here]Ok. This school makes me confused. The summary of t.docx
[Type here]Ok. This school makes me confused. The summary of t.docx
 
© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx
© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx
© 2020 Cengage Learning®. May not be scanned, copied or duplic.docx
 
© 2016 Laureate Education, Inc. Page 1 of 3 RWRCOEL Prof.docx
© 2016 Laureate Education, Inc.   Page 1 of 3 RWRCOEL Prof.docx© 2016 Laureate Education, Inc.   Page 1 of 3 RWRCOEL Prof.docx
© 2016 Laureate Education, Inc. Page 1 of 3 RWRCOEL Prof.docx
 
© 2022 Post University, ALL RIGHTS RESERVED Due Date.docx
© 2022 Post University, ALL RIGHTS RESERVED  Due Date.docx© 2022 Post University, ALL RIGHTS RESERVED  Due Date.docx
© 2022 Post University, ALL RIGHTS RESERVED Due Date.docx
 
{DiscriminationGENERAL DISCRIMINATI.docx
{DiscriminationGENERAL DISCRIMINATI.docx{DiscriminationGENERAL DISCRIMINATI.docx
{DiscriminationGENERAL DISCRIMINATI.docx
 
~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx
~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx
~UEER THEORY AND THE JEWISH QUESTI01 Daniel Boyarin, Da.docx
 
© 2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx
©  2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx©  2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx
© 2017 Cengage Learning. All Rights Reserved.Chapter Twelve.docx
 
`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx
`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx
`HISTORY 252AEarly Modern Europe from 1500 to 1815Dr. Burton .docx
 
^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx
^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx
^ Acadumy of Management Journal2001. Vol. 44. No. 2. 219-237.docx
 
`Inclusiveness. The main.docx
`Inclusiveness. The main.docx`Inclusiveness. The main.docx
`Inclusiveness. The main.docx
 
__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx
__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx
__MACOSXSujan Poster._CNA320 Poster Presentation rubric.pdf.docx
 

Recently uploaded

How to Add Chatter in the odoo 17 ERP Module
How to Add Chatter in the odoo 17 ERP ModuleHow to Add Chatter in the odoo 17 ERP Module
How to Add Chatter in the odoo 17 ERP Module
Celine George
 
RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3
RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3
RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3
IreneSebastianRueco1
 
Thesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.pptThesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.ppt
EverAndrsGuerraGuerr
 
Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46
Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46
Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46
MysoreMuleSoftMeetup
 
Digital Artifact 2 - Investigating Pavilion Designs
Digital Artifact 2 - Investigating Pavilion DesignsDigital Artifact 2 - Investigating Pavilion Designs
Digital Artifact 2 - Investigating Pavilion Designs
chanes7
 
The simplified electron and muon model, Oscillating Spacetime: The Foundation...
The simplified electron and muon model, Oscillating Spacetime: The Foundation...The simplified electron and muon model, Oscillating Spacetime: The Foundation...
The simplified electron and muon model, Oscillating Spacetime: The Foundation...
RitikBhardwaj56
 
Digital Artefact 1 - Tiny Home Environmental Design
Digital Artefact 1 - Tiny Home Environmental DesignDigital Artefact 1 - Tiny Home Environmental Design
Digital Artefact 1 - Tiny Home Environmental Design
amberjdewit93
 
Top five deadliest dog breeds in America
Top five deadliest dog breeds in AmericaTop five deadliest dog breeds in America
Top five deadliest dog breeds in America
Bisnar Chase Personal Injury Attorneys
 
Lapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdfLapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdf
Jean Carlos Nunes Paixão
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
Peter Windle
 
The basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptxThe basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptx
heathfieldcps1
 
ANATOMY AND BIOMECHANICS OF HIP JOINT.pdf
ANATOMY AND BIOMECHANICS OF HIP JOINT.pdfANATOMY AND BIOMECHANICS OF HIP JOINT.pdf
ANATOMY AND BIOMECHANICS OF HIP JOINT.pdf
Priyankaranawat4
 
Best Digital Marketing Institute In NOIDA
Best Digital Marketing Institute In NOIDABest Digital Marketing Institute In NOIDA
Best Digital Marketing Institute In NOIDA
deeptiverma2406
 
Azure Interview Questions and Answers PDF By ScholarHat
Azure Interview Questions and Answers PDF By ScholarHatAzure Interview Questions and Answers PDF By ScholarHat
Azure Interview Questions and Answers PDF By ScholarHat
Scholarhat
 
Executive Directors Chat Leveraging AI for Diversity, Equity, and Inclusion
Executive Directors Chat  Leveraging AI for Diversity, Equity, and InclusionExecutive Directors Chat  Leveraging AI for Diversity, Equity, and Inclusion
Executive Directors Chat Leveraging AI for Diversity, Equity, and Inclusion
TechSoup
 
Introduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp NetworkIntroduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp Network
TechSoup
 
Pride Month Slides 2024 David Douglas School District
Pride Month Slides 2024 David Douglas School DistrictPride Month Slides 2024 David Douglas School District
Pride Month Slides 2024 David Douglas School District
David Douglas School District
 
S1-Introduction-Biopesticides in ICM.pptx
S1-Introduction-Biopesticides in ICM.pptxS1-Introduction-Biopesticides in ICM.pptx
S1-Introduction-Biopesticides in ICM.pptx
tarandeep35
 
The Diamonds of 2023-2024 in the IGRA collection
The Diamonds of 2023-2024 in the IGRA collectionThe Diamonds of 2023-2024 in the IGRA collection
The Diamonds of 2023-2024 in the IGRA collection
Israel Genealogy Research Association
 
South African Journal of Science: Writing with integrity workshop (2024)
South African Journal of Science: Writing with integrity workshop (2024)South African Journal of Science: Writing with integrity workshop (2024)
South African Journal of Science: Writing with integrity workshop (2024)
Academy of Science of South Africa
 

Recently uploaded (20)

How to Add Chatter in the odoo 17 ERP Module
How to Add Chatter in the odoo 17 ERP ModuleHow to Add Chatter in the odoo 17 ERP Module
How to Add Chatter in the odoo 17 ERP Module
 
RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3
RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3
RPMS TEMPLATE FOR SCHOOL YEAR 2023-2024 FOR TEACHER 1 TO TEACHER 3
 
Thesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.pptThesis Statement for students diagnonsed withADHD.ppt
Thesis Statement for students diagnonsed withADHD.ppt
 
Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46
Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46
Mule 4.6 & Java 17 Upgrade | MuleSoft Mysore Meetup #46
 
Digital Artifact 2 - Investigating Pavilion Designs
Digital Artifact 2 - Investigating Pavilion DesignsDigital Artifact 2 - Investigating Pavilion Designs
Digital Artifact 2 - Investigating Pavilion Designs
 
The simplified electron and muon model, Oscillating Spacetime: The Foundation...
The simplified electron and muon model, Oscillating Spacetime: The Foundation...The simplified electron and muon model, Oscillating Spacetime: The Foundation...
The simplified electron and muon model, Oscillating Spacetime: The Foundation...
 
Digital Artefact 1 - Tiny Home Environmental Design
Digital Artefact 1 - Tiny Home Environmental DesignDigital Artefact 1 - Tiny Home Environmental Design
Digital Artefact 1 - Tiny Home Environmental Design
 
Top five deadliest dog breeds in America
Top five deadliest dog breeds in AmericaTop five deadliest dog breeds in America
Top five deadliest dog breeds in America
 
Lapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdfLapbook sobre os Regimes Totalitários.pdf
Lapbook sobre os Regimes Totalitários.pdf
 
A Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in EducationA Strategic Approach: GenAI in Education
A Strategic Approach: GenAI in Education
 
The basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptxThe basics of sentences session 5pptx.pptx
The basics of sentences session 5pptx.pptx
 
ANATOMY AND BIOMECHANICS OF HIP JOINT.pdf
ANATOMY AND BIOMECHANICS OF HIP JOINT.pdfANATOMY AND BIOMECHANICS OF HIP JOINT.pdf
ANATOMY AND BIOMECHANICS OF HIP JOINT.pdf
 
Best Digital Marketing Institute In NOIDA
Best Digital Marketing Institute In NOIDABest Digital Marketing Institute In NOIDA
Best Digital Marketing Institute In NOIDA
 
Azure Interview Questions and Answers PDF By ScholarHat
Azure Interview Questions and Answers PDF By ScholarHatAzure Interview Questions and Answers PDF By ScholarHat
Azure Interview Questions and Answers PDF By ScholarHat
 
Executive Directors Chat Leveraging AI for Diversity, Equity, and Inclusion
Executive Directors Chat  Leveraging AI for Diversity, Equity, and InclusionExecutive Directors Chat  Leveraging AI for Diversity, Equity, and Inclusion
Executive Directors Chat Leveraging AI for Diversity, Equity, and Inclusion
 
Introduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp NetworkIntroduction to AI for Nonprofits with Tapp Network
Introduction to AI for Nonprofits with Tapp Network
 
Pride Month Slides 2024 David Douglas School District
Pride Month Slides 2024 David Douglas School DistrictPride Month Slides 2024 David Douglas School District
Pride Month Slides 2024 David Douglas School District
 
S1-Introduction-Biopesticides in ICM.pptx
S1-Introduction-Biopesticides in ICM.pptxS1-Introduction-Biopesticides in ICM.pptx
S1-Introduction-Biopesticides in ICM.pptx
 
The Diamonds of 2023-2024 in the IGRA collection
The Diamonds of 2023-2024 in the IGRA collectionThe Diamonds of 2023-2024 in the IGRA collection
The Diamonds of 2023-2024 in the IGRA collection
 
South African Journal of Science: Writing with integrity workshop (2024)
South African Journal of Science: Writing with integrity workshop (2024)South African Journal of Science: Writing with integrity workshop (2024)
South African Journal of Science: Writing with integrity workshop (2024)
 

Foundations of Materials Science and Engineering, 5th Edn. Sm.docx

  • 1. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display CHAPTER 3 Crystal and Amorphous Structure in Materials Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 2 The Space Lattice and Unit Cells • Atoms, arranged in repetitive 3-Dimensional pattern, in long range order (LRO) give rise to crystal structure. • Properties of solids depends upon crystal structure and
  • 2. bonding force. • An imaginary network of lines, with atoms at intersection of lines, representing the arrangement of atoms is called space lattice. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Building blocks 3 LEGO block Unit cell http://loyalkng.com/2010/03/21/lego-ironman-from-brickshelfs- legodreams-the-ironman-goes-lego/ Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 4 Unit cell
  • 3. • Unit cell is that block of atoms which repeats itself to form space lattice. • Materials arranged in short range order are called amorphous materials Unit Cell Space Lattice Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 5 Crystal Systems and Bravais Lattice • Only seven different types of unit cells are necessary to create all point lattices. • According to Bravais (1811-1863) fourteen standard unit cells can describe all possible lattice networks. • The four basic types of unit cells are
  • 4. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 6 Types of Unit Cells • Cubic Unit Cell • Tetragonal Simple Body Centered Face centered Simple Body Centered Figure 3.2 Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
  • 5. 7 Types of Unit Cells (Cont..) • Orthorhombic ≠ b ≠ c • Rhombohedral Simple Base Centered Face Centered Body Centered Simple Figure 3.2 Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 8 Types of Unit Cells (Cont..) • Hexagonal
  • 6. • Monoclinic • Triclinic Simple Simple Simple Base Centered Figure 3.2 Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 9 Principal Metallic Crystal Structures • 90% of the metals have either Body Centered Cubic (BCC), Face Centered Cubic (FCC) or Hexagonal Close Packed (HCP) crystal structure.
  • 7. • HCP is denser version of simple hexagonal crystal structure. BCC Structure FCC Structure HCP Structure Figure 3.3 Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 10 Body Centered Cubic (BCC) Crystal Structure • Represented as one atom at each corner of cube and one at the center of cube. • Each atom has 8 nearest neighbors. • Therefore, coordination number is 8. • Examples :- Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission
  • 8. required for reproduction or display 11 BCC Crystal Structure (Cont..) • Each unit cell has eight 1/8 atom at corners and 1 full atom at the center. • Therefore each unit cell has • Atoms contact each other at cube diagonal (8x1/8 ) + 1 = 2 atoms 3 4RTherefore, a = Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 12 Atomic Packing Factor of BCC Structure Atomic Packing Factor = Volume of atoms in unit cell Volume of unit cell
  • 9. Vatoms = = 8.373R3 3 3 4 = 12.32 R3 Therefore APF = 8.723 R 3 12.32 R3 = 0.68 V unit cell = a3 =
  • 10. 3 4 .2 3R Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 13 Face Centered Cubic (FCC) Crystal Structure • FCC structure is represented as one atom each at the corner of cube and at the center of each cube face. • Coordination number for FCC structure is 12 • Atomic Packing Factor is 0.74 • Examples :- old (a = 0.408)
  • 11. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 14 FCC Crystal Structure (Cont..) • Each unit cell has eight 1/8 atom at corners and six ½ atoms at the center of six faces. • Therefore each unit cell has • Atoms contact each other across cubic face diagonal (8 x 1/8)+ (6 x ½) = 4 atoms 2 4RTherefore, lattice constant a = Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission
  • 12. required for reproduction or display 15 Hexagonal Close-Packed Structure • The HCP structure is represented as an atom at each of 12 corners of a hexagonal prism, 2 atoms at top and bottom face and 3 atoms in between top and bottom face. • Atoms attain higher APF by attaining HCP structure than simple hexagonal structure. • The coordination number is 12, APF = 0.74. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 16 HCP Crystal Structure (Cont..) • Each atom has six 1/6 atoms at each of top and bottom layer, two half atoms at top and bottom layer and 3 full atoms at the middle layer. • Therefore each HCP unit cell has • Examples:-
  • 13. • Ideal c/a ratio is 1.633. (2 x 6 x 1/6) + (2 x ½) + 3 = 6 atoms Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display YouTube videos links • http://www.youtube.com/watch?v=Rm- i1c7zr6Q • http://www.youtube.com/watch?v=F4Du 4zI4GJ0 • http://www.youtube.com/watch?v=vYky UqUa6vU • http://www.youtube.com/watch?v=NYV SI83KiKU 17 http://www.youtube.com/watch?v=Rm-i1c7zr6Q http://www.youtube.com/watch?v=F4Du4zI4GJ0 http://www.youtube.com/watch?v=vYkyUqUa6vU http://www.youtube.com/watch?v=NYVSI83KiKU Foundations of Materials Science and Engineering, 5th Edn.
  • 14. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 18 Atom Positions in Cubic Unit Cells • Cartesian coordinate system is use to locate atoms. • In a cubic unit cell posite of positive directions. • Atom positions are located using unit distances along the axes. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 19 Directions in Cubic Unit Cells • In cubic crystals, Direction Indices are vector components of directions resolved along each axes, resolved to smallest
  • 15. integers. • Direction indices are position coordinates of unit cell where the direction vector emerges from cell surface, converted to integers. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 20 Procedure to Find Direction Indices (0,0,0) (1,1/2,1) z Produce the direction vector till it emerges from surface of cubic cell Determine the coordinates of point of emergence and origin Subtract coordinates of point of Emergence by that of origin (1,1/2,1) - (0,0,0) = (1,1/2,1) Are all are
  • 16. integers? Convert them to smallest possible integer by multiplying by an integer. 2 x (1,1/2,1) = (2,1,2) Are any of the direction vectors negative? Represent the indices in a square bracket without comas with a over negative index (Eg: [121]) Represent the indices in a square bracket without comas (Eg: [212] ) The direction indices are [212] x y YES NO YES NO
  • 17. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 21 Direction Indices - Example • Determine direction indices of the given vector. Origin coordinates are (3/4 , 0 , 1/4). Emergence coordinates are (1/4, 1/2, 1/2). Subtracting origin coordinates from emergence coordinates, (3/4 , 0 , 1/4) - (1/4, 1/2, 1/2) = (-1/2, 1/2, 1/4) Multiply by 4 to convert all fractions to integers 4 x (-1/2, 1/2, 1/4) = (-2, 2, 1) Therefore, the direction indices are [ 2 2 1 ] Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 22 Miller Indices
  • 18. • Miller Indices are are used to refer to specific lattice planes of atoms. • They are reciprocals of the fractional intercepts (with fractions cleared) that the plane makes with the crystallographic x,y and z axes of three nonparallel edges of the cubic unit cell. z x y Miller Indices =(111) Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 23 Miller Indices - Procedure Choose a plane that does not pass through origin Determine the x,y and z intercepts of the plane Find the reciprocals of the intercepts
  • 19. Fractions? Clear fractions by multiplying by an integer to determine smallest set of whole numbers Enclose in parenthesis (hkl)where h,k,l are miller indicesof cubic crystal plane forx,y and z axes. Eg: (111) Place a ‘bar’ over the Negative indices Yes Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Miller Indices - Examples • Intercepts of the plane at x,y & z axes are 1, ∞ and ∞ • Taking reciprocals we get (1,0,0). • Miller indices are (100).
  • 20. ******************* • Intercepts are 1/3, 2/3 & 1. • taking reciprocals we get (3, 3/2, 1). • Multiplying by 2 to clear fractions, we get (6,3,2). • Miller indices are (632). x x y z (100) Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display Miller Indices - Examples • Plot the plane (101) Taking reciprocals of the indices we get (1 ∞ 1). The intercepts of the plane are x=1, y= ∞ (parallel to y) and z=1.
  • 21. ****************************** • Plot the plane (2 2 1) Taking reciprocals of the indices we get (1/2 1/2 1). The intercepts of the plane are x=1/2, y= 1/2 and z=1. Figure EP3.7 a Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 26 Miller Indices - Example • Plot the plane (110) The reciprocals are (1,-1, ∞) The intercepts are x=1, y=-1 and z= ∞ (parallel to z axis) To show this plane in a single unit cell, the origin is moved along the positive direction of y axis by 1 unit. x y z(110)
  • 22. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 27 Miller Indices – Important Relationship • Direction indices of a direction perpendicular to a crystal plane are same as miller indices of the plane. • Example:- • Interplanar spacing between parallel closest planes with same miller indices is given by lkh d a hkl 222 ++ = Figure EP3.7b Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi
  • 23. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 28 Planes and Directions in Hexagonal Unit Cells • Four indices are used (hkil) called as Miller- Bravais indices. • Four axes are used (a1, a2, a3 and c). • Reciprocal of the intercepts that a crystal plane makes with the a1, a2, a3 and c axes give the h,k,I and l indices respectively. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 29 Hexagonal Unit Cell - Examples • Basal Planes:- Intercepts a1 = ∞ a2 = ∞ a3 = ∞ c = 1 (hkli) = (0001)
  • 24. • Prism Planes :- For plane ABCD, Intercepts a1 = 1 a2 = ∞ a3 = -1 c = ∞ (hkli) = (1010) Figure 3.17 a&b Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 30 Directions in HCP Unit Cells • Indicated by 4 indices [uvtw]. • u,v,t and w are lattice vectors in a1, a2, a3 and c directions respectively. • Example:- For a1, a2, a3 directions, the direction indices are [ 2 1 1 0], [1 2 1 0] and [ 1 1 2 0] respectively.
  • 25. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 31 Comparison of FCC and HCP crystals • Both FCC and HCP are close packed and have APF 0.74. • FCC crystal is close packed in (111) plane while HCP is close packed in (0001) plane. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 32 Structural Difference between HCP and FCC Consider a layer of atoms (Plane ‘A’) Another layer (plane ‘B’) of atoms is placed in ‘a’ Void of plane ‘A’
  • 26. Third layer of Atoms placed in ‘b’ Voids of plane ‘B’. (Identical to plane ‘A’.) HCP crystal. Third layer of Atoms placed in ‘a’ voids of plane ‘B’. Resulting In 3rd Plane C. FCC crystal. Plane A ‘a’ void ‘b’ void Plane A Plane B ‘a’ void ‘b’ void Plane A Plane B Plane A Plane A Plane B Plane C Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
  • 27. 33 Volume Density • Volume density of metal = • Example:- Copper (FCC) has atomic mass of 63.54 g/mol and atomic radius of 0.1278 nm. vρ Mass/Unit cellVolume/Unit cell= a= 2 4R = 2 1278.04 nm× = 0.361 nm Volume of unit cell = V= a3 = (0.361nm)3 = 4.7 x 10-29 m3 vρ FCC unit cell has 4 atoms. Mass of unit cell = m =
  • 28. × − g Mg molatmos molgatoms 6 23 10 /107.4 )/54.63)(4( = 4.22 x 10-28 Mg 33329 28 98.898.8 107.4 1022.4
  • 29. cm g m Mg m Mg V m == × × == − − Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 34
  • 30. Planar Atomic Density • Planar atomic density= • Example:- In Iron (BCC, a=0.287), The (100) plane intersects center of 5 atoms (Four ¼ and 1 full atom). Area of 110 plane = ρ p= Equivalent number of atoms whose centers are intersected by selected area Selected area 222 aaa =× ρ p ( )2287.02 2 = 2 13 2 1072.12.17 mmnm
  • 31. atoms × == Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 35 Linear Atomic Density • Linear atomic density = • Example:- For a FCC copper crystal (a=0.361), the [110] direction intersects 2 half diameters and 1 full diameter. Length of line = ρ l = Number of atomic diameters intersected by selected length of line in direction of interest Selected length of line mm
  • 32. atoms nm atoms nm atoms 61092.392.3 361.02 2 × == × =ρ l nm361.02 × Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 36 Polymorphism or Allotropy • Metals exist in more than one crystalline form. This is
  • 33. caller polymorphism or allotropy. • Temperature and pressure leads to change in crystalline forms. • Example:- Iron exists in both BCC and FCC form depending on the temperature. -2730C 9120C 13940C 15390C α Iron BCC γ Iron FCC δ Iron BCC Liquid Iron Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 37 Crystal Structure Analysis • Information about crystal structure are obtained using X- Rays.
  • 34. • The X-rays used are about the same wavelength (0.05- 0.25 nm) as distance between crystal lattice planes. 35 KV (Eg: Molybdenum) Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display X-Ray Spectrum of Molybdenum • X-Ray spectrum of Molybdenum is obtained when Molybdenum is used as target metal. • Kα and Kβ are characteristic of an element. • For Molybdenum Kα occurs at wave length of about 0.07nm. • Electrons of n=1 shell of target metal are knocked out by bombarding electrons. • Electrons of higher level drop down by releasing energy to replace lost electrons
  • 35. 48 Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 39 X-Ray Diffraction • Crystal planes of target metal act as mirrors reflecting X- ray beam. • If rays leaving a set of planes are out of phase (as in case of arbitrary angle of incidence) no reinforced beam is produced. • If rays leaving are in phase, reinforced beams are produced. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display
  • 36. 40 X-Ray Diffraction (Cont..) • For rays reflected from different planes to be in phase, the extra distance traveled by a ray should be a integral multiple of wave length λ . nλ = MP + PN (n = 1,2…) n is order of diffraction If dhkl is interplanar distance, Then MP = PN = dhkl.Sinθ Therefore, λ = 2 dhkl.Sinθ After A.G. Guy and J.J. Hren, “Elements of Physical Metallurgy,” 3d ed., Addison-Wesley, 1974, p.201.) Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 41 Interpreting Diffraction Data • We know that 2
  • 38. = ++ = λ θ θ λ θλSince Note that the wavelength λ and lattice constant a are the same For both incoming and outgoing radiation. Substituting for d, Therefore Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 42 Interpreting Diffraction Data (Cont..) • For planes ‘A’ and ‘B’ we get two equations 2
  • 40. = λ θ λ θ (For plane ‘A’) (For plane ‘B’) Dividing each other, we get )( )( 222 222 2 2 BBB AAA B A lkh lkh Sin
  • 41. Sin ++ ++ = θ θ Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 43 X-Ray Diffraction Analysis • Powdered specimen is used for X-ray diffraction analysis as the random orientation facilitates different angle of incidence. • Radiation counter detects angle and intensity of diffracted beam. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi
  • 42. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 44 Diffraction Condition for Cubic Cells • For BCC structure, diffraction occurs only on planes whose miller indices when added together total to an even number. I.e. (h+k+l) = even Reflections present (h+k+l) = odd Reflections absent • For FCC structure, diffraction occurs only on planes whose miller indices are either all even or all odd. I.e. (h,k,l) all even Reflections present (h,k,l) all odd Reflections present (h,k,l) not all even or all odd Reflections absent. Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 45 Interpreting Experimental Data • For BCC crystals, the first two sets of diffracting planes are {110} and {200} planes.
  • 43. Therefore • For FCC crystals the first two sets of diffracting planes are {111} and {200} planes Therefore 5.0 )002( )011( 222 222 2 2 = ++ ++ = B A Sin Sin θ θ
  • 44. 75.0 )002( )111( 222 222 2 2 = ++ ++ = B A Sin Sin θ θ Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi
  • 45. Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 46 Crystal Structure of Unknown Metal Unknown metal Crystallographic Analysis FCC Crystal Structure BCC Crystal Structure 75.02 2 = B A Sin Sin θ θ 5.0
  • 46. 2 2 = B A Sin Sin θ θ Foundations of Materials Science and Engineering, 5th Edn. Smith and Hashemi Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display 47 Amorphous Materials • Random spatial positions of atoms • Polymers: Secondary bonds do not allow formation of parallel and tightly packed chains during solidification. micrystalline.
  • 47. • Glass is a ceramic made up of SiO4 4- tetrahedron subunits – limited mobility. • Rapid cooling of metals (10 8 K/s) can give rise to amorphous structure (metallic glass). • Metallic glass has superior metallic properties. Definitions • Crystal structure: the manner in which atoms, ions and molecules are spatially arranged • Lattice: a three dimensional array of points coinciding with atom positions • Allotropy: a property of an element to coexist in more than one crystal structure • Amorphous materials: materials like glasses that have no long range order or crystal structure • Isotropic: having same properties in all directions • Anisotropic: property of materials that have different properties in different directions • Unit cell: subdivision of a crystal structure into small repeat entities • Basis or motif: a group of atoms associated with a lattice point • Coordination number: number of nearest neighbors of an atom in a crystal structure • Atomic packing fraction: fraction of plane, volume or direction that is actually occupied by atoms • Lattice parameter: the unit cell edge lengths and angle between them • Closed packed directions: directions in a crystal lattice along which atoms are in contact
  • 48. Definitions • Cubic site: an interstitial site with coordination number of eight • Tetrahedral site: an interstitial site with coordination number of four • Octahedral site: an interstitial site with coordination number of six • Bravais lattice: fourteen possible lattice arrangements that are possible using lattice points in 3D space • Miller indices: a notation used to describe specific crystallographic planes and directions • Miller indices of directions: are vector components of the directions resolved along each of the coordinate axes • Miller indices of planes: are defined as reciprocals of fractional intercepts that the planes makes with coordinate axes • Metallic glass: metals with an amorphous atomic structure • Linear atomic density: the number of lattice points per unit length along a direction • Planar density: the number of atoms whose centers are intersected by the plane per unit area • Volume density: the ratio of mass per unit volume of a unit cell Ch03-revised-D2LCHAPTER �3The Space Lattice and Unit CellsBuilding blocksUnit cellCrystal Systems and Bravais LatticeTypes of Unit CellsTypes of Unit Cells (Cont..)Types of Unit Cells (Cont..)Principal Metallic Crystal Structures Body Centered Cubic (BCC) Crystal StructureBCC Crystal Structure (Cont..)Atomic Packing Factor of BCC Structure Face Centered Cubic (FCC) Crystal StructureFCC Crystal Structure
  • 49. (Cont..)Hexagonal Close-Packed StructureHCP Crystal Structure (Cont..)YouTube videos linksAtom Positions in Cubic Unit CellsDirections in Cubic Unit CellsProcedure to Find Direction IndicesDirection Indices - ExampleMiller IndicesMiller Indices - ProcedureMiller Indices - ExamplesMiller Indices - ExamplesMiller Indices - ExampleMiller Indices – Important RelationshipPlanes and Directions in Hexagonal Unit Cells Hexagonal Unit Cell - ExamplesDirections in HCP Unit CellsComparison of FCC and HCP crystalsStructural Difference between HCP and FCCVolume DensityPlanar Atomic DensityLinear Atomic DensityPolymorphism or AllotropyCrystal Structure AnalysisX- Ray Spectrum of MolybdenumX-Ray DiffractionX-Ray Diffraction (Cont..)Interpreting Diffraction DataInterpreting Diffraction Data (Cont..)X-Ray Diffraction AnalysisDiffraction Condition for Cubic CellsInterpreting Experimental DataCrystal Structure of Unknown MetalAmorphous MaterialsDefinitions- ch-3DefinitionsDefinitions ENGR 1210 HW 3 1 Homework 3 on chapter 3; (Total points: 100) Reading assignments: Chapter 3 from textbook, notes and slides Student Name: _______________________________ MTSU ID: ____________________ Honor pledge: I _______________________________ acknowledge that I have neither received
  • 50. nor given any unauthorized help/aid during this assignment. Part 1 Key Engineering Terms: fill in the blanks – 25 points 1. Crystal structure: The manner in which atoms, ions and molecules are _____________________________________ arranged. 2. Lattice: A three dimensional array of points coinciding with ________________________________ positions. 3. Unit cell: A ____________________ of lattice into small _________________________ entities still retaining overall characteristics of the entire lattice. 4. Basis or motif: a group of atoms associated with _____________________________. 5. Crystalline material: A crystalline material is one in which the atoms are situated in a _____________________________________ or periodic array over ________________________________ atomic distances. 6. Coordination number: number of ________________________________ neighbors of an atom in a crystal structure. 7. Lattice parameter: The unit cell
  • 51. ___________________________ and the _________________________ between the edges. 8. Closed packed direction: direction in a crystal lattice along which atoms are in _________________________________. 2 9. Bravais lattices: _______________________________ possible lattices arrangements using lattice points in 3 dimensional space. 10. Atomic packing fraction: a fraction of a plane, volume or direction that is _____________________________ occupied with atoms. 11. Allotropy or Polymorphism: a property of an element to coexist in more than ________________________________ crystal structures. 12. Amorphous Materials: Materials including glasses that have ______________________________ long range order or crystal structure. 13. Isotropic: Having _________________________________
  • 52. properties in all directions. 14. Anisotropic: Having _________________________________ properties in different directions. 15. Miller Indices of Directions: Are _____________________________ components of the directions resolved along each of the coordinate axes. 16. Miller Indices of Planes: Are _____________________________ of fractional _________________________________ that plane makes with coordinate axes. 17. Linear density: It is defined as the number of lattice points or atomic diameters per unit ____________________________________ of the direction. 18. Planar density: The number of atoms whose ________________________________ are intersected by the plane per unit _____________________________. 19. X-ray diffraction: A technique to analyze the _____________________________ of materials using a beam of X-rays as source. 20. Metallic glass: Metals with ____________________________ crystal structure.
  • 53. 3 Part 2 Learning concepts/reflections/problems – 65 points 1. Sketch the unit cells of Simple Cubic, Body Centered Cubic and Face Centered Cubic lattices and determine and show calculations for following: A. Number of atoms per unit cell B. Equation/relation for radius and lattice parameter (unit cell edge length) C. Atomic Packing Fraction (APF) 15 points 2. Calculate the radius of a palladium (Pd) atom, given that Pd has an FCC crystal structure, a density of 12.0 g/cm3, and an atomic weight of 106.4 g/mol. Assume Avogadro’s number = 6.022 x 1023 atoms/mol 5 points 3. Determine the Miller Indices of directions A, B, C and D as shown in figure below: 10 points
  • 54. 4 4. Determine Miller Indices of planes as shown in figure below: 10 points 5. Determine Miller Bravais Indices [hkil] of directions as shown in figure below: 10 points 5 6. Determine Miller Bravais Indices (hkil) of planes as shown in figure below: 10 points 7. Define diffraction. Write an expression for Bragg’s law of diffraction and explain the terms of the equation. 5 points
  • 55. Part 3 Materials design – 10 points 1. Why metallic crystal structure are dense? Explain. 5 points 2. Give 2 materials examples of each of the following crystal structures: a. Simple cubic (SC) b. Body Centered Cubuc (BCC) c. Face Centered Cubic (FCC) d. Hexagonal Closed Packed (HCP) 5 points 6 Bonus questions: 1. Explain why the properties of polycrystalline materials are most often isotropic? 5 points 2. Explain two differences between an optical microscope and a scanning electron microscope (SEM). 5 points 3. Calculate theoretical density of Chromium which has Body
  • 56. Centered Cubic structure and atomic weight of 52 g/mol and atomic radius of 0.125 nm. Assume Avogadro’s number = 6.022 x 1023 atoms/mol 5 points Note: Please use extra sheets wherever necessary to answer the questions. All HW must be uploaded via D2L Dropbox system. Students are highly encouraged to refer textbook, notes and slides.