Introduction
(Lecture 1)
Material Science
• field of science that studies the relationships between the microstructure, synthesis
and processing, and properties of materials
• Factors such as material microstructure, chemical composition, synthesis and
processing, and performance to cost ratio, are all related
• Material microstructure refers to the arrangement of the atoms of the material,
• synthesis refers to the extraction of materials from there natural state
• processing refers to the shaping of materials into useful forms.
Materials Engineering
• field that focuses on how to transform materials into products, by applying
knowledge of materials
• example, in designing an engine block for a car.
o need to assess the materials that are available - material would need to be strong
and able to withstand high temperatures from fuel combustion
o need to consider manufacturing processes for the engine block.
o machining is selected to create the engine block - select an appropriate tool for
machining, and specify lubricants types
Classes of Materials
• generally five classes of materials:
1. Metals and alloys
2. Ceramics, glasses and glass ceramics
3. Polymers
4. Composites
5. Semiconductors
• Mechanical, electrical and physical properties differ across classes of materials
o Metals and alloys tend to have high density, and high strength
o Composites tend to have low density and high strength
o Polymers tend to have low density and medium/low strength
Metals and their alloys:
• Metals refers to the pure state of a metallic material
• Alloys are pure metals that have small additions of other elements - Done to improve
the properties of metal
• Known for high strength, good ductility, good resistance to shock
• Good thermal and electrical conductivity
• Common metals: steel (iron and carbon), aluminium, zinc, copper, titanium, nickel
etc.
• Metals are crystalline – atoms are orderly arranged
,Ceramic and glass:
• Ceramics are crystalline, inorganic materials – consist of metallic and non-metallic
elements
• Have high temperature resistance/ melting points
• Poor conductors of electricity and heat
• High strength in compression and tension
• Low elongation – brittle
• High hardness – good wear resistance
• Advanced ceramics (alumina, silicon nitride, silicon carbide) are used in spark plugs,
electrical insulation, sensors etc.
Glass:
• Glass is an amorphous material, derived from silica
• Amorphous - Atoms are not arranged in a specific order or pattern
• Strength of glass can be improved by heat treatment - tempering
Polymers:
• Polymers are produced by a process called polymerisation
• Good electrical resistivity, and good resistance to heat transfer (good insulators)
• Low densities
• Cannot be used at high temperatures – low softening and decomposition
temperatures
• Two categories:
o Thermosetting polymers (right)
- Molecular chains are crossed linked
- Stronger but more brittle
o thermoplastic polymers (left)
- molecular chains are entangled
- good formability and ductility
, Semiconductors:
• known as electronic materials - used in computers and electronic circuits
• common semiconductors are silicon, germanium, and gallium arsenide
• have properties between that of a metal and insulator
• there are two types:
o Intrinsic
- Properties (i.e. conductivity) are affected by temperature
o Extrinsic
- Properties (i.e. conductivity) are dependent on the amount of dopant atoms
- Dopant atoms include aluminium, boron, phosphorous, arsenic etc.
Composite materials:
• Produced by blending two or more different materials together
• Creates a new material with UNIQUE properties
• Generally lightweight, and strong
• Common composites include
o fibrous
- fibres are imbedded in a matrix
o particulate
- particles are imbedded in a matrix
• examples – fibreglass, reinforced concrete and plywood
(Lecture 1)
Material Science
• field of science that studies the relationships between the microstructure, synthesis
and processing, and properties of materials
• Factors such as material microstructure, chemical composition, synthesis and
processing, and performance to cost ratio, are all related
• Material microstructure refers to the arrangement of the atoms of the material,
• synthesis refers to the extraction of materials from there natural state
• processing refers to the shaping of materials into useful forms.
Materials Engineering
• field that focuses on how to transform materials into products, by applying
knowledge of materials
• example, in designing an engine block for a car.
o need to assess the materials that are available - material would need to be strong
and able to withstand high temperatures from fuel combustion
o need to consider manufacturing processes for the engine block.
o machining is selected to create the engine block - select an appropriate tool for
machining, and specify lubricants types
Classes of Materials
• generally five classes of materials:
1. Metals and alloys
2. Ceramics, glasses and glass ceramics
3. Polymers
4. Composites
5. Semiconductors
• Mechanical, electrical and physical properties differ across classes of materials
o Metals and alloys tend to have high density, and high strength
o Composites tend to have low density and high strength
o Polymers tend to have low density and medium/low strength
Metals and their alloys:
• Metals refers to the pure state of a metallic material
• Alloys are pure metals that have small additions of other elements - Done to improve
the properties of metal
• Known for high strength, good ductility, good resistance to shock
• Good thermal and electrical conductivity
• Common metals: steel (iron and carbon), aluminium, zinc, copper, titanium, nickel
etc.
• Metals are crystalline – atoms are orderly arranged
,Ceramic and glass:
• Ceramics are crystalline, inorganic materials – consist of metallic and non-metallic
elements
• Have high temperature resistance/ melting points
• Poor conductors of electricity and heat
• High strength in compression and tension
• Low elongation – brittle
• High hardness – good wear resistance
• Advanced ceramics (alumina, silicon nitride, silicon carbide) are used in spark plugs,
electrical insulation, sensors etc.
Glass:
• Glass is an amorphous material, derived from silica
• Amorphous - Atoms are not arranged in a specific order or pattern
• Strength of glass can be improved by heat treatment - tempering
Polymers:
• Polymers are produced by a process called polymerisation
• Good electrical resistivity, and good resistance to heat transfer (good insulators)
• Low densities
• Cannot be used at high temperatures – low softening and decomposition
temperatures
• Two categories:
o Thermosetting polymers (right)
- Molecular chains are crossed linked
- Stronger but more brittle
o thermoplastic polymers (left)
- molecular chains are entangled
- good formability and ductility
, Semiconductors:
• known as electronic materials - used in computers and electronic circuits
• common semiconductors are silicon, germanium, and gallium arsenide
• have properties between that of a metal and insulator
• there are two types:
o Intrinsic
- Properties (i.e. conductivity) are affected by temperature
o Extrinsic
- Properties (i.e. conductivity) are dependent on the amount of dopant atoms
- Dopant atoms include aluminium, boron, phosphorous, arsenic etc.
Composite materials:
• Produced by blending two or more different materials together
• Creates a new material with UNIQUE properties
• Generally lightweight, and strong
• Common composites include
o fibrous
- fibres are imbedded in a matrix
o particulate
- particles are imbedded in a matrix
• examples – fibreglass, reinforced concrete and plywood
