3. PURE METALS AND ALLOYS
Metal that are not mixed with any other materials are known as pure metals.
Metals listed in the Periodic Table are pure metals
E.g. Iron (Fe), Copper (Cu) and Zinc (Zn)
Alloys are mixtures of two or more metals formed together with other
elements/materials to create new metals with improved Mechanical Properties
and other properties of the base metal.
E.g. Brass (Copper and Zinc),
Stainless steel (steel and chromium)
Alloy = metal A + metal B + … + other elements
4. Pure Metals Alloys
Iron
Copper
Aluminium
Lead
Zinc
Tin
Gold
(a mixture of two or more materials)
Brass ( Copper & Zinc)
Steel (Iron & Carbon)
Cast Iron (Iron & Carbon)
Duralium (Aluminium & Copper)
Bronze (Copper, Tin, Phosphorus)
High Speed Steel (Tungsten,
Chromium, Carbon, Vanadium &
Molybdenum)
5. FERROUS METALS & NON-FERROUS METALS
Ferrous metals are metals that contain iron
E.g. Steel (iron and carbon)
Non-ferrous metals are metals that do not contain iron
E.g. Zinc (pure metal), Bronze (Copper and tin)
(non-ferrous may contain slight traces of iron)
Ferrous Metal = alloy metals that contains iron
( Primary base metal is iron)
Non-ferrous Metal = alloy metals that do not contain iron
Primary base metal does not contain iron)
6. These metals can be further subdivided
Ferrous Metals Non Ferrous Metals
(Containing Iron) (Containing No Iron)
Wrought Iron
Steel
Cast Iron
Copper
Aluminium
Lead
Zinc
Tin
Gold
Brass
Duralium
Bronze
7. EXTRACTION OF IRON
•Iron is found in iron oxide in the earth.
•Three primary iron ores: magnetite, hematite, taconite
•Iron is extracted using blast furnace
•Steps in extraction of iron
Ores is washed, crushed and mixed with limestone and coke
The mixture is fed into the furnace and is then melted
Coke(a product of coal, mainly carbon) is used to convert the iron
oxides to iron
8. EXTRACTION OF IRON
Limestone helps to separate the impurities from the metal
The liquid waste is known as slag that floats on the molten iron
They are then tapped off (separated)
The iron produced is only about 90% to 95% pure.
The iron is then further refined using the basic oxygen furnace and the
electric arc furnace to produce steel which is widely used now.
9. Ferrous Materials -:Ferrous metals and alloys are widely used because they
provide a wide range of properties that are not found in other family of materials.
The principle ferrous metals commonly used in engineering practice are
(i)Wrought iron (ii)Steels (iii) cast iron
The raws materials for all ferrous metal in pig iron. Pig iron is obtained by
melting the iron in a blast furnace with the help of coke and lime-stone.
11. CAST IRONS
By remelting pig iron along with iron scraps and limestone in a cupola furnace, Cast Iron (CI) is obtained.
Thus cast iron may be called as modified pig iron.
Although cast iron is brittle and has lower strength properties than most steels, it has certain advantages
and characteristics:
It is the least expensive casting material
Cast Iron has lower melting temperature (1130 – 1200°C) than steel (1380 –
1540°C), hence it can easily be cast.
They have very high compressive strength, about 3 to 4 times that of its tensile
strength. The base of heavy machinery are made of cast iron.
Cast Iron can be machined easily (good machinability)
They provide high wear and abrasion resistance.
Because of high carbon content, they have self lubricating properties, hence
guide ways on machine bed are made of cast iron.
14. CAST IRONS
Cast Iron has high Damping Capacity. It is the
property which permits a material to absorb
vibrational load. The figure shows the Damping
Capacity of cast iron as compared to steel.
15. Cast iron –: This is a primarily an alloy of iron and carbon. The carbon in cast
iron varies form 2.1% to 6.67%. The melting temperature of cast iron is in the range
of 1150-1250 C.
The various types of cast iron in use are as follows
◦ i) Grey cast iron
◦ ii) White cast iron
◦ iii) Malleable cast iron
◦ iv) Ductile cast iron
16. Effect of the alloy materials on cast iron-:
1. Silicon -: It also helps to produce ,sound casting free from blow-holes.
2. Sulphur -: It makes the cast iron hard and brittle.
3. Manganese -: It may be present in cast iron upto 0.75%.It makes the cast
iron white and hard.
4. Phosphorus-: It’s content in cast iron varies between 0.05 to 1.00%.
5. Carbon -: If carbon is present in combined form, it makes the iron
hard and strong.
28. Steels -: In alloy of carbon and iron with carbon content
usually ranges from 0.08 to 1.5 %. The melting temperature of
steel is in the range of 1350-1400 C.
The carbon steels can be classified on the basis of their
carbon content as -:
i) Low carbon steel
ii) Medium carbon steel
iii) High carbon steel
29. 29
Low Carbon Steel
Also known as mild steel
Contain 0.08% -0.3% carbon
Tough, ductile and malleable
Easily joined and welded
Poor resistance to corrosion
Often used a general purpose material
Nails, screws, car bodies,
Structural Steel used in the construction industry
30. 30
Medium Carbon Steel
Contains 0.3% - 0.6% of carbon
Offer more strength and hardness BUT
less ductile and malleable
Structural steel, rails and garden tools
31. 31
High Carbon Steel
Also known as ‘tool steel’
Contain 0.6%-1.5% carbon
Very hard but offers Higher
Strength Less ductile
and less malleable
Hand tools (chisels, punches)
Saw blades
32. 32
Stainless Steel
Steel alloyed with
chromium (18%), nickel (8%), magnesium (8%)
Hard and tough
Corrosion resistance
Comes in different grades
Sinks, cooking utensils, surgical instruments
33. 33
Applications of Steel
• Construction: Reinforcing bars made of steel are used to strengthen concrete structures
• Automobiles: vehicle bodies, chassis, and various components.
• Railways: Steel is used in the construction of railway tracks, bridges, and rolling stock,
including train cars.
• Oil and Gas Pipelines.
• Machinery and Equipment:
• Tools: Many hand tools and machine tools are made from steel
• Appliances such as refrigerators, ovens, and washing machines
• Military Vehicles
• Surgical instruments
• Kitchenware
35. Aluminium and aluminium alloys
• It is ductile and malleable due to FCC structure.
• It is light in weight (specific gravity 2.7g/cm3)
• It has very good thermal & electrical conductivity on weight-to-weight basis.
• It has excellent ability of getting alloyed with other elements like Cu, Si, Mg,
Zn etc….
• Pure form of aluminum is used for photo graphic reflectors to take advantage of
its light reflectivity characteristics.
• Al is non-toxic, non-magnetic and non-sparking.
• Good machinability & work ability
36. • Aluminum may be alloyed with one or more alloying elements such as
copper, manganese, magnesium, silicon and nickel.
• The addition of small quantities of alloying elements converts the soft
and weak aluminum into hard and strong metal, while it retains its
light weight.
The main alloys of aluminum are:
• Duralumin,
• Y-alloy and
• Magnalium
37. Duralumin: (Aluminium- 92 %), Copper – (3.5 to 4.5%), Magnesium- 0.4 to
0.7%, iron and silicon (0.7%), Manganese (0.4 to 7%) Duralumin can be
highly strengthened by heat treatment. It is as strong as steel but weighs only
one third of the weight of steel.
Y-alloy: Y- alloy consists of ( Aluminium- 93%, Copper – 2%, Nickel- 2%,
Magnesium- 1%, ) Y- alloy is good conductor of heat and is available in both
wrought and cast forms.
39. Conductors
Aluminum is an electric as well as heat conductor.
• Wires are an example for electrical conductors
41. Transport
• Aluminum and its alloys have been the prime material of construction
for the aircraft and the cars.
42. Sports cars and aluminum
• Being light weight and durable aluminum has revolutionized the
motor sports industry.
Corvette Z06 in 2006
Corvette Z06 chassis
The all-aluminum space frame of the 2006 Z06 Corvette resulted in a 30% reduction in weight.
43. Packaging
• The most significant use of aluminum in packaging has been in the
production of beverage cans.
44. Building and Architecture
• Aluminum is used in buildings for a wide spectrum of applications.
These include roofing and windows.
45. High Pressure Gas Cylinders
• Compressed gas cylinders with capacities up to 50l capacity for
storage and transportation of CO2, air, oxygen and gasoline.
46. Sporting Goods
• The aluminum alloys are used for golf clubs and trolleys, racquets for
many sports, snooker and pool cues.
47. Road Barriers and Signs
• aluminum being corrosion resistant and tough they are widely used as
road barriers and signs.
48. Aluminum Ladders
• Aluminum alloys are highly suited to ladders and access equipment
being lightweight, corrosion resistant and tough.
49. Physical properties of copper and copper alloys
Crystal structure FCC
Atomic number 29
Atomic weight 63.546
Density (g.cm-3) 8.933
Melting point (oC) 1084.62
Electrical and thermal
conductivities of
pure metals at RT
• High ductility,
formability.
•High electrical and
thermal
conductivities.
Cu
29
Copper
63.546
FCC
50. Copper and Copper alloys
• High Thermal Conductivity
• High Electrical Conductivity
• Good Corrosion Resistance
• High Malleability and Ductility
• Good formability
• Antimicrobial Properties
52. INTRODUCTION – CERAMICS
The word ‘ceramic’ is originated from greek word keromikos, which
means ‘burnt stuff’.
Ceramics: Inorganic compounds that contain metallic and non-metallic
elements, for which inter-atomic bonding is ionic, and which are generally
formed at high temperatures.
57. CLASSIFICATION – CERAMICS
Ceramics are classified in many ways. It is due to divergence in
composition, properties and applications.
Based on their composition, ceramics are:
- Oxides (aluminum oxide (Al2O3), silicon dioxide (SiO2)
- Carbides (silicon carbide (SiC), tungsten carbide (WC), titanium carbide (TiC))
- Nitride (silicon nitride (Si3N4), boron nitride (BN), and titanium nitride (TiN))
- Sulfides (Zinc sulfide (ZnS), Lead Sulfide)
- Fluorides (Sodium fluoride (NaF), potassium fluoride (KF))
58. CLASSIFICATION – CERAMICS
Based on their specific applications, ceramics are classified as:
Glasses
Clay products
Refractories
Abrasives
Cements
60. CLASSIFICATION – CERAMICS
Based on their engineering applications, ceramics are classified into two
groups as: traditional and engineering ceramics.
Traditional ceramics – most made-up of clay, silica and feldspar
Engineering ceramics – these consist of highly purified aluminium oxide
(Al2O3), silicon carbide (SiC) and silicon nitiride (Si3N4)
61. CLAY PRODUCTS
-earthenware e.g. plant pot
(dirty red brown, very cheap,
opaque)
-stoneware e.g. coffee mug,
plate, bowl
(cheap, heavy, opaque)
earthenware stoneware porcelain bone china
-porcelain e.g. table wares
plate, souvenirs
(clean, light, translucency)
-bone china e.g. table wares, souvenirs
(very clean, very expensive,
very good translucency,
light, mostly ivory colour)
62. REFRACTORY
• A material to use in high temperature furnaces.
• Consider Silica (SiO2) - Alumina (Al2O3) system.
mullite, alumina, and crystobalite (made up of SiO2)
tetrahedra as candidate refractories.
Refractory
63. 63
Glasses are non-crystalline silicates
containing with other oxides , e.g., CaO,
Na2O, K2O and Al2O3.
Mostly glasses are transparent and easy
to fabricate or form.
Glass-ceramics are glasses which are
transformed to crystalline state with
fine polycrystalline grains.
High strength,
high thermal conductivity, high
thermal shock resistance ,e.g., Pyrex
GLASS
64. ABRASIVES
• Tools:
--for grinding and polishing
--for cutting
--for oil drilling
Abrasive blades
oil drill bits
•Because of their hardness,
high wear resistance,
high toughness
67. WHAT IS A COMPOSITE?
A composite is a structural material, that consists of two or more
constituents that are combined at macroscopic level and not
soluble in each other.
Examples:
Flesh in your leg reinforced with bones
Concrete reinforced with steel
Epoxy reinforced with graphite fibers.
69. Alloy Composite
An Alloy is a mixture of one or more metals with
other elements.
Composites are also a mixture of two or more
elements, but it does not contain metals.
An alloy can either be a homogeneous or a
heterogeneous mixture. A composite is always a heterogeneous mixture.
Alloys are lustrous due to the presence of metals in
their composition.
Composites are not lustrous as they do not contain
metal in their composition.
Most alloys can conduct electricity.
Composites do not conduct electricity except for
metal matrix composites.
the element getting introduced (solute) dissolves
into the metal getting alloyed (solvent) to form a
solid solution. Cannot be distinguished
the component forming the base of the composite
(matrix) and the added element remain undissolved
and could be identified
Steel, Bronze, Brass etc. Human Bones, Plywood, Concrete etc.
72. • Specific stiffness and specific strength
• Tailorable design
• Fatigue Life
• Dimensional Stability
• Corrosion Resistance
• Cost Effective Fabrication
• Light in weight
• Conductivity
Advantages of Composite Materials
73. • High initial cost of tooling, production set-up, etc
• Training of the labour is essential
• Labour intensive
• Health and safety concerns
• Inspection may require special tools and processes
• The matrix material is weak and hence the composite has low toughness
• The analysis of the composites is difficult due to heterogeneity
Disadvantages of Composite Materials
111. ENR116 – Mod. 4- Slide No. 111
Properties:
Tm for glass is moderate, but large for other ceramics.
low toughness and ductility; large moduli and creep resistance
Glasses Clay
products
Refractories Abrasives Cements Advanced
ceramics
-optical
-composite
reinforce
-containers/
household
-whiteware
-bricks
-bricks for
high T
(furnaces)
-sandpaper
-cutting
-polishing
-composites
-structural
engine
-rotors
-valves
-bearings
-sensors
Adapted from Fig. 13.1 and discussion in
Section 13.2-6, Callister & Rethwisch 8e.
Classes of ceramics
#111: As listed here, there are many different types of ceramic materials
These ceramic materials find use in a varied range of applications, from windows to sandpaper to bearings in an engine
In general, the ceramic materials have high melting temperatures, low toughness and ductility, and large elastic moduli and resistance to creep
In this presentation, each of the classes of ceramic materials will be introduced, highlighting the properties and applications of the ceramics
For select ceramic materials, their manufacturing will be discussed
