The document discusses various properties of engineering materials that are important for mechanical design. It describes six main families of materials - metals, ceramics, glasses, polymers, elastomers, and hybrid materials. Within each family, materials share common properties, such as ceramics being hard, brittle, and corrosion resistant, while metals are ductile, tough, and good conductors. The document outlines key mechanical, thermal, electrical, optical, environmental resistance, and eco-friendly properties of materials. It emphasizes that successful design requires matching the right material with the required properties for the application.

1. ENGINEERING
MATERIALS AND TEIR
PROPERTIES
DISUSUN OLEH:
FITRI HANDAYANI (0804102010003)
ANDRIANSYAH (0804102010025)
JURUSAN TEKNIK MESIN
FAKULTAS TEKNIK
UNIVERSITAS SYIAH KUALA
2010

2. INTRODUCTION
a) Material boleh dikatakan sebagai makanan dari
design.
b) Suksesnya produk dilihat dari:
 tampilan yang baik yaitu memiliki nilai uang dan
memberikan kepuasan kepada si pengguna
 menggunakan material terbaik untuk pekerjaan
tersebut dengan memanfaatkan sepenuhnya
potensi dan karakterstik yang ada.
a) Material yang kita cari adalah material yang ciri
dan sifat tertentu.
b) Material yang bagus adalah material yang telah
kita ketahui moduli, strength , damping
capacities, konduktivitas listrik dan thermal.

3. The Families of Engineering Material
Steels, Cast
Irons, Al-
alloys
Metals
Cu-alloys,
Zn-alloys, Ti-
alloys
Aluminas, PP, PE, PC,
Silicon PS, PA,
PMMK
Ceramic
carbidas
Plastics
composites,
sandwichses Phenolics,
Zirconia
Expoxies
Hybrids
segmented
structures,
lattices weaves
Soda glass, Isoprene, Neo
borosillicate prene, Butyl
glass. rubber
Glasses Elastomers
Silica glasses, Natural rubber
Glass- Silicons EVA
ceramics

4. The Material Properties
 General properties :
1) Densitas
2) Harga
 Mechanical properties : Metals
ζu
1) ultimate strength
Stress ζ = F/Ao
2) Compressive strength
2) Failure strength
3) Hardness ζy Ao F
4) Fatique endurance limit
5) Thoughness L
6) Damping capacity Slope E = ζ/ε
0.2% offset
X Brittle: T << Tg Polymers
Strain ε = δL/L
Polymers
Ao F
Stress ζ = F/Ao
Limited plasticity: T = 0.8 Tg
ζy Cold drawing: T = Tg
L
Viscous flow: T >> Tg
1% strain
Strai ε = δL/L

5.  Thermal properties:
1) melting point
2) Glass temperatur
3) Maximum service
4) Minimum service
5) Specific heat
6) Thermal conduktivity
7) Thermal expansion coefficient
8) Thermal shock resistance
 Electrical properties:
1) Electrical resistivity
2) Diaelectric constant
3) Breakdownpotential
4) Power factor
 Optical properties:
optical, transfarent, translucent, opaq
ue, Referactive index.
 E-co properties: energy/kg to
extract material, CO2 /kg to extract
material.
 Environmental resistance
properties: Corrotion
rates, Oxidation rates, wear rate
constant.

6. Mechanical Properties
Kekuatan pada keramik dan glass
bergantung dengan kekuatan
pada bentuk pembebanan.
Intension, ‘‘strength’’ berarti ζf (compression)
Ceramics
kekuatan sebelum patah, tIn Compression
compression itu maksudnya the
Stress ζ = F/Ao
Ao
crushing strength c, yang
memiliki daerah yang lebih luas Slope E = σ/ε
dengan tipe tersendiri. L
ζt (tension)
Tension
Strain ε = δL/L

7. Endurance limit Ao ∆F
Stress amplitude ∆ζ
ζu
L
107
Endurance limit cycles
∆ζe
Hardness is measured as the load P
divided by the projected area of
contact, A, when a diamond-shaped
indenter is forced into the surface.
The endurance limit, e, is the
cyclic stress that causes failure in Nf
¼ 107 cycles.

8. Fracture toughness
ζc
The fracture toughness, KIC,
Stress ζ = F/Ao
measures the resistance to the
propagation of a crack.
The failure strength of a brittle solid 2c
containing a crack of length 2c is KIC
¼ Y ð ,where Y is a constant near
unity. K1C = ζc(πa)
1/2

9. Loss coefficient
Area
∆U
A ∆F
= F/Ao
The loss-coefficient, (a Area
U
dimensionless quantity),
measures the degree to which a
material dissipates vibrational
energy (Figure 3.9). If a
material is loaded elastically to a
stress, max, it stores an elastic
energy per unit volume. If it is
loaded and then unloaded, it
dissipates an energy
I
U ¼ d"

10. Thermal Properties
Two temperatures, the melting Thermal conductivity
T T2
temperature, Tm, and the glass
temperature, Tg (units for both: K X
or C) are fundamental because they
relate directly to the strength of the
Heat flux q
bonds in the solid. Crystalline Heat Heat
solids have a sharp melting point, input sink
q W/m2 q W/m2
Tm. Non-crystalline solids do not; the
temperature Tg characterizes the
transition from true solid to very
viscous liquid. It is helpful, in
engineering nsulation Sample
design, to define two further Slope λ ∆T
temperatures: the maximum and q =− λ
∆X
minimum service temperatures Tmax
and Tmin (both: K or C).
Temperature gradient (T1 T2)/X

11. Thermal Expansion
The thermal strain per
degree of temperature change is Thermal expansion
measured by the linear thermal- ∆L
α= 1
Thermal strain ε = δL/L
expansion coefficient, (units: K Slope α
1 or, more conveniently, as L ∆T
‘‘microstrain/C’’ or 10 6 C 1). If
the material is thermally isotropic,
the volume expansion, per degree, is L
3 . If it is anisotropic, two or more
coefficients are required, and the
volume expansion becomes the sum
of the principal thermal strains. ∆L
The thermal shock α
resistance Ts (units: K or C) is
the maximum tem- perature
difference through which a
material can be quenched Insulation Heater Sample
suddenly without damage. It,
and the creep resistance, are
important in high- temperature Temperature change
design.
∆T

12. Electrical Properties
The electrical conductivity is simply
the reciprocal of the resisitivity.
When an insulator is placed in an Electrical resistivity
Potential difference ∆V
electric field, it becomes polarized
and charges appear on its surfaces ∆V
that tend to screen the interior
ι ι
from the electric field. The
tendency to polarize is measured X
by the dielectric constant, Ed (a Area A
dimensionless quantity). Its value Resistance Resistivity
for free space and, for practical R = ∆V/ι ∆V A
ρe =
purposes, for most gasses, is 1. X ι
Most insulators have values Current ι
between 2 and 30, though low-
density foams approach the value 1
because they are largely air.

13. Optical Properties
All materials allow some passage of
light, although for metals it is exceed-
ingly small. The speed of light when in
the material, v, is always less than
that in vacuum, c. A consequence is that
a beam of light striking the surface of
such a material at an angle , the
angle of incidence, enters the material at
an angle , the angle of refraction.

14. Eco - Properties
 The contained or production energy (units
MJ/kg) is the energy required to extract 1
kg of a material from its ores and
feedstocks. The associated CO2 production
(units: kg/kg) is the mass of carbon dioxide
released into the atmosphere during the
production of 1 kg of material.

15. Environmental Properties
Environmental resistance is
conventionally characterized on a 3.4 Summ
discrete
5-point scale: very good, good, Wear rate
average, poor, very poor. ‘‘Very good’’ P3 P2 P1
means
Wear volume V
that the material is highly resistant
to the environment, ‘‘very poor’’ that
it is completely non-resistant or Load P
unstable. The categorization is
Sliding
designed to help with initial W = V/S velocity v
screening; supporting information
should always be sought if
environmental attack is a concern.
Ways of doing this are described
later.

16. Summary
 There are six important families of materials for
mechanical design: metals, ceramics, glasses, polymers,
elastomers, and hybrids that combine the properties of
two or more of the others.
 Within a family there is certain common ground:
ceramics as a family are hard, brittle, and corrosion
resistant; metals are ductile, tough, and good thermal
and electrical conductors; polymers are light, easily
shaped, and electrical insulators, and so on — that is
what makes the classification useful.
 In design we wish to escape from the constraints of family,
and think, instead, of the material name as an identifier
for a certain property-profile

17. THANK YOU