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Types of Material
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Why Materials ???
Ashby,: Material Selection
in Mechanical Design
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Engineering Materials
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Materials
Nanomaterials, shape-memory alloys, superconductors,
Ferrous metals: carbon-, alloy-, stainless-, tool-and-die steels
Non-ferrous metals: aluminum, magnesium, copper, nickel,
titanium, superalloys, refractory metals,
beryllium, zirconium, low-melting alloys,
gold, silver, platinum,
Plastics: thermoplastics (acrylic, nylon, polyethylene, ABS,)
thermosets (epoxies, Polymides, Phenolics, )
elastomers (rubbers, silicones, polyurethanes, )
Ceramics, Glasses, Graphite, Diamond, Cubic Boron Nitride
Composites: reinforced plastics, metal-, ceramic matrix composites
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Properties of materials
Mechanical properties of materials
Strength, Toughness, Hardness, Ductility,
Elasticity, Fatigue and Creep
Chemical properties
Oxidation, Corrosion, Flammability, Toxicity,
Physical properties
Density, Specific heat, Melting and boiling point,
Thermal expansion and conductivity,
Electrical and magnetic properties
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Material Specification
Chemical composition
Mechanical properties Strength, hardness
(under various conditions: temperature,
humidity, pressure)
Physical properties density, optical,
electrical, magnetic
Environmental green, recycling
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Metals
Ferrous Metals
Cast irons
Steels
Super alloys Iron-based
Nickel-based
Cobalt-based
Non-ferrous metals
Aluminum and its alloys
Copper and its alloys
Magnesium and its alloys Nickel and its alloys
Titanium and its alloys
Zinc and its alloys Lead & Tin
Refractory metals
Precious metals
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General Properties and Applications of
Ferrous Alloys
Ferrous alloys are useful metals in terms of
mechanical, physical and chemical properties.
Alloys contain iron as theirbase metal. Car bon steels are least expensive of all metals
while stainless steels is costly.
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Carbon and alloy steels
Carbon steels
Classified as low, medium and high:
1. Low-carbon steel or mild steel, < 0.3%C,
bolts, nuts and sheet plates.
2. Medium-carbon steel, 0.3% ~ 0.6%C,
machinery, automotive and agricultural
equipment.
3. High-carbon steel, > 0.60% C, springs,
cutlery, cable.
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Carbon and alloy steels
Alloy steels
Steels containing significant amounts of
alloying elements.
Structural-grade alloy steels used forconstruction industries due to high strength.
Other alloy steels are used for its strength,
hardness, resistance to creep and fatigue, andtoughness.
It may heat treated to obtain the desired
properties.
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Carbon and alloy steels
High-strength low-alloy steels
Improved strength-to-weight ratio.
Used in automobile
bodies to reduce weig
htand in agricultural equipment.
Some examples are:
1. Dual-phase steels2. Micro alloyed steels
3. Nano-alloyed steels
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Stainless steels
Characterized by their corrosion resistance,high strength and ductility, and high
chromium content.
Stainless as a film ofchromium oxide protects
the metal from corrosion.
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Stainless steels
Five types of stainless steels:
1. Austenitic steels
2. Ferritic steels3. Martensitic steels
4. Precipitation-hardening (PH) steels
5. Duplex-structure steels
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Typical Selection of Carbon and Alloy Steels
for Various Applications
TAB L E 5 . 1
P ro d u ct S tee l P ro d u ct S tee l
Aircraft forgings,
tu b ing, f it t ings
A u tomo b i le b odies
Axles
Bal l b ear ings and races
Bolts
C a m sh aftsC h ains ( transmission)
Coil spr ings
Connect ing rods
Cranksh afts (forged )
4140 , 8740
1010
1040 , 4140
52100
1035, 4042, 4815
1020 , 10403135 , 3140
4063
1040, 3141, 4340
1045, 1145, 3135, 3140
Differential gears
G ears (car and truck)
Landing gear
Lock w ash ers
N u ts
Rai l road ra i ls and w h eels
Spr ings (coi l )Springs ( leaf)
T u b in g
W ire
W i re (mus ic)
4023
4027 , 4032
4140 , 4340 , 8740
1060
3130
1080
1095 , 4063 , 61501085 , 4063 , 9260 , 6150
1040
1045 , 1055
1085
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Mechanical Properties of Selected Carbon and
Alloy Steels in Various Conditions
TABLE 5.2 Typical Mechanical Properties of Selected Carbon and Alloy Steels in the Hot-Rolled,
Normalized, and Annealed Condition
AISI Condition Ultimate
tensile
strength
(MPa)
Yield
Strength
(MPa)
Elongation in
50 mm (%)
Reduction of
area (%)
Hardness
(HB)
1020
1080
3140
4340
8620
As-rolled
NormalizedAnnealed
As-rolled
Normalized
Annealed
Normalized
Annealed
Normalized
AnnealedNormalized
Annealed
448
441393
1010
965
615
891
689
1279
744632
536
346
330294
586
524
375
599
422
861
472385
357
36
3536
12
11
24
19
24
12
2226
31
59
6766
17
20
45
57
50
36
4959
62
143
131111
293
293
174
262
197
363
217183
149
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AISI Designation for High-Strength Sheet
Steel
TABLE 5.3
Yield Strength Chemical
Composition
Deoxidation
Practice
psi x 103
MPa
35
40
4550
60
7080
100120
140
240
275
310350
415
485550
690830
970
S = structural alloy
X = low alloy
W = weathering
D = dual phase
F = killed plus sulfide inclusion control
K = killed
O = nonkilled
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Room-Temperature Mechanical Properties and
Applications of Annealed Stainless SteelsTABLE 5.4 Room-Temperature Mechanical Properties and Typical App lications of S elected Annealed
Stainless Steels
AISI
( S)
ltimate
te sile
stre gt
( a)
iel
stre gt
( a)
Elo gatio
i 50 mm
( ) aracteristics a ty ical a licatio s
30 3
(S30300)
550620 240260 5350 Scre machine products, shafts, valves, bolts,
bushings, and nuts; aircraft fittings; bolts; nuts;
rivets; scre s; studs.30 4
(S30400)
565620 240290 6055 hemical and food pro cessing equipment,
bre ing equipment, cryogenic vessels, gutters,
do nspouts, and flashings.
31 6
(S31600)
550590 210290 6055 igh corrosion resistance and hig h creep strength.
hemical and pulp handling equipment,
photographic equipment, brandy vats, fertilizer
parts, ketchup cooking kettles, and yeast tubs.
41 0(S41000)
480520 240310 3525 Machine parts, pump shafts, bolts, bushings, coalchutes, cutlery, tackle, hard are, jet engine parts,
mining machinery, rifle barrels, scre s, and
valves.
41 6
(S41600)
480520 275 3020 Aircraft fittings, bolts, nuts, fire extinguisher
inserts, rivets, and scre s.
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Tool and die steels
Designed forhigh strength, impact toughness,and wear resistance at a range of
temperatures.
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Basic Types of Tool and Die Steels
TABLE 5.5
Type AISI
High speed
Hot work
Cold work
Shock resisting
Mold steels
Special purpose
Waterhardening
M (molybdenum base)
T (tungsten base)
H1 to H19 (chromium base)
H20 to H39 (tungsten base)
H40 to H59 (molybdenum base)D (high carbon, high chromium)
A (medium alloy, airhardening)
O (oil hardening)
S
P1 to P19 (low carbon)
P20 to P39 (others)
L (low alloy)F (carbon-tungsten)
W
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Processing and Service Characteristics of
Common Tool and Die Steels
TABLE 5.6 Processing and Service Characteristics of Common Tool and Die Steels
AISI
desig
atio
esista
ce to
decar
rizatio
esista
ce to
cracki
g
Appro imate
ardness
(
) ac ina ility To g ness
esistance to
softening
esistance to
ear
2 edium edium 6065 edium o
ery high Very high
T1 igh High 6065 edium o Very high Very high
T5 o
edium 6065 edium o Highest Very high
H11, 12, 13 edium Highest 3855 edium to high Very high High Medium
2 Medium Highest 5762 Medium Medium High High
A9 Medium Highest 3556 Medium High High Medium to
high
D2 Medium Highest 5461
o
o
High High to very
high
D3 Medium High 5461 o
o High Very high
H21 Medium High 3654 Medium High High Medium to
high
H26 Medium High 4358 Medium Medium Very high High
P20 High High 2837 Medium to high High Lo Lo to
medium
P21 High Highest 3040 Medium Medium Medium Medium
W1, W2 Highest Medium 5064 Highest High Lo Lo tomedium
Source: Adapted rom Tool teels, American Iron and teel Institute, 1978.
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Aluminium and aluminium alloys
Factors for selecting are:1. High strength to weight ratio
2. Resistance to corrosion
3. High thermal and electrical conductivity4. Ease of machinability
5. Non-magnetic
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Magnesium and magnesium alloys
Magnesium (Mg) is the lightest metal. Alloys are used in structural and non-
structural applications.
Typical uses of magnesium alloys are aircraftand missile components.
Also has good vibration-damping
characteristics.
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Copper and copper alloys
Copper alloys have electrical and mechanical
properties, corrosion resistance, thermal
conductivity and wear resistance.
Applications are electronic components,
springs and heat exchangers.
Brass is an alloy of copper and zinc.
Bronze is an alloy of copper and tin.
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Nickel and nickel alloys
Nickel(Ni) has strength, toughness, and
corrosion resistance to metals.
Used in stainless steels and nickel-base
alloys.
Alloys are used forhigh temperatureapplications, such as et-engine components
and rockets.
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Superalloys
Superalloys are high-temperature alloys use
in et engines, gas turbines and reciprocatingengines.
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Titanium and titanium alloys
Titanium (Ti) is expensive, has high strength-
to-weight ratio and corrosion resistance.
Used as components for aircrafts, et-engines,
racing-cars and marine crafts.
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Refractory metals
Refractory metals have a high melting point
and retain their strength at elevated
temperatures.
Applications are electronics, nuclear power
and chemical industries.
Molybdenum, columbium, tungsten, and
tantalum are referred to as refractory metal.
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Other nonferrous metals
1. Beryllium
2. Zirconium
3. Low-melting-point metals:- Lead
- Zinc
- Tin
4. Precious metals:
- Gold
- Silver
- Platinum
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Special metals and alloys
1. Shape-memory alloys (i.e. eyeglass frame, helical
spring)
2. Amorphous alloys (Metallic
Glass)
3. Nanomaterials
4. Metal foams
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Heat Treatment of Metals
Annealing Full annealing
Normalising (faster rate of cooling)
Recovery annealing (longerh
olding time,slower rate of cooling,)
Stress relieving (lower temperature)
Martensite formation in steel
Austenitizing (conversion to austenite)
Quenching (control cooling rate
Tempering (reduce brittleness)
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Heat Treatment of Metals
Precipitation hardening
Solution treatment (E-phase conversion)
quenching
precipitation treatment (aging)
Surface hardening
Carburizing
Nitriding Carbonitriding
Chromizing and Boronizing
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Heat Treatment of Steel
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Precipitation Hardening
Solution treatment
Quenching
Precipitation treatment
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Furnaces for Heat Treatment
Fuel fire furnaces gas
oil
Electric furnacesbatch furnaces
box furnaces - door
car-bottom furnaces - track for moving large parts
bell-type furnaces - cover/bell lifted by gantry crane
continuous furnaces
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Furnaces for Heat Treatment
Vacuum furnaces
Salt-bath furnaces
Fluidized-bed furnaces
Some of the furnaces have special atmosphere
requirements, such as carbon- and
nitrogen- rich atmosphere.
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Surface Hardening Methods
Flame hardening
Induction heating
High-frequency resistance heating
Electron beam heating
Laserbeam heating
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Surface Hardening Methods
Induction
heating
High frequency
resistance
heating
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Classification of Ceramics
Ceramics
Traditional ceramics
New ceramics
Glass
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Ceramics
Traditional ceramics
clays: kaolinite
silica: quartz, sandstone
alumina
silicon carbide
New ceramics
oxide ceramics : alumina carbides : silicon carbide, titanium carbide, etc.
nitrides : silicon nitride, boron nitiride, etc.
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Glass
Glass products
window glass
containers
light bulb glass
laboratory glass
glass fibers
optical glass Glass ceramics - polycrystalline structure
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Classification of Polymers
Thermoplastics
Thermosets
Elastomers
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Polymers
Thermoplastics - reversible in phase by heating
and cooling. Solid phase at room temperature
and liquid phase at elevated temperature.
Thermosets - irreversible in phase by heatingand cooling. Change to liquid phase when
heated, then follow with an irreversible
exothermic c
hemical reaction. Remain in solidphase subsequently.
Elastomers - Rubbers
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Thermoplastics
Acetals
Acrylics - PMMA
Acrylonitrile-Butadiene-Styrene - ABS
Cellulosics
Fluoropolymers - PTFE , Teflon
Polyamides (PA) - Nylons, Kevlar
Polysters - PET
Polyethylene (PE) - HDPE, LDPE Polypropylene (PP)
Polystyrene (PS)
Polyvinyl ch
loride (PVC)
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Thermosets
Amino resins
Epoxies
Phenolics
Polyesters
Polyurethanes
Silicones
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Elastomers
Natural rubber
Synthetic rubbersbutadiene rubber
butyl rubber
chloroprene rubber
ethylene-propylene rubber
isoprene rubber
nitrile rubber
polyurethanes
silicones
styrene-butadiene rubber
thermoplastic elastomers
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Classification of Composite Materials
Metal Matrix Composites
Ceramic Matrix Composites
Polymer Matrix Composites
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Composite Materials
Metal Matrix Composites (MMC)Mixture of ceramics and metals reinforced by strong,
high-stiffness fibers
Ceramic Matrix Composites (CMC)
Ceramics such as aluminum oxide and silicon carbide
embedded with fibers for improved properties,
especially high temperature applications.
Polymer Matrix Composites (PMC)Thermosets or thermoplastics mixed with fiber
reinforcement or powder.
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Composite Materials
1D fibre
Woven fabric
Random fibre
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Composite Materials
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Taxonomy of Materials Selection
Ashby,: Material Selection
in Mechanical Design
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