This PPT deals with the structure of materials, in Engineering Materials

1. By
N. Kiran
Assistant Professor
St.Peter’s Engineering College
Hyderabad

2. STRUCTURE OF MATERIALS

3.  All elements can exists as either solid, liquid,
or gases depending upon the condition of
temperature and pressure.
 State of matter in which the substance posses
rigidity and tendency to maintain both its
shape and volume.

4.  Based on internal arrangement of atoms
 All the solid materials can be classified as
1) Crystalline solids
2) Amorphous Solids

6. Anisotropy Isotropy

8.  Several crystals are bounded together then
the resulting solid is called polycrystalline
solids.

13. Simple cubic
1/8 x 8 = 1
BCC
1/8 X 8=1
1X1=1
=2
FCC
1/8 X 8=1
1/2X 6= 3
= 4
HCP
2(1/6X6)= 2
3X1=3
1/2X2=1
=6

15.  Crystallization or solidification
 process of transition from the liquid to solid
state.
 When the molten metal is cooled
 The whole mass does not solidify
instantaneously.

16.  It comprises of two steps
1) Nucleation
The formation of stable nuclei in the melt
2) Grain or Crystal Growth
growth of nuclei into crystal and the
formation of the grain structure

18.  Crystals of irregular shape are called grains
 Interface separating two adjoining grains is
called grain boundary.

21.  Rate of whole crystallization depends on two
factors
 1) Rate of nucleation (N)
The number of crystals nucleating per unit
time per unit volume
2) Rate of crystal growth (G)
The rate at which linear size of a crystal
increases

24.  Distorted elongated grains
 High strength and hardness
 Low ductility

25.  1) Recovery
 2) Re-crystallization
 3) Grain Growth