SECTION 1

LU 1: Introduction to
Materials Science and
Engineering

Reference: Callister Jr, W. D., & Rethwisch, D. G. (2020). Callister's materials science
and engineering. John Wiley & Sons.
 Module Outcomes (MO)
o Analyze different properties of materials.

Learning Outcomes (LOs)

o LO1: Distinguish between Material Science and Material
Engineering.

o LO2: Apply property classifications of materials to determine a

materials applicability.

o LO3: Evaluate the decision-making criteria during material design

and selection.

©McGraw-Hill Education
 What are Materials?
What are “materials”? According to Webster’s dictionary,
materials may be defined as substances of which something is
composed or made. Although this definition is broad, from an
engineering application point of view, it covers almost all relevant
situations.
Where do materials come from?
Earth’s crust: metals, ceramics, and electronic materials are mined in the form
of ores and processed to produce pure metals, nonmetals, alloys, and
compounds.
Laboratory or Factory: Polymers and composites are mostly manmade and are
synthesized in laboratories using chemical and thermal/mechanical processes.

Examples: Silicon (electronic material) and Iron (structural materials)

constitute 28% and 5% of weight of earths crust, respectively. PVC (polymer)
and fiberglass (a composite) is made in a laboratory or a factory.
 Materials Science and Engineering
Materials science deals with basic knowledge about the
internal structure, properties and processing of
materials.
Materials engineering deals with the application of
knowledge gained by materials science to convert
materials to products.
 Cont…
Structure of a material: arrangement of material’s
internal components. It is classified according to size:
Subatomic Nanostructure
Relates to the electrons Relates to the
within individual atoms accumulation of atoms to
form crystals (<100nm)
Courtesy of Chemistry Libretexts

Atomic Microstructure
Relates to the arrangement of
atoms to form crystals Relates to the
accumulation of atoms to
Courtesy of
form crystals (>100nm)
Britannica

Macrostructure
Structural elements with scale
range between several mm to
the order of m
©McGraw-Hill Education
 Cont..
Important properties of solid materials to determine
material applicability:
Mechanical properties: relates deformation of the material in response to an
applied load or force (e.g. elastic modulus (stiffness), strength, resistance to
fracture)

Electrical properties: material response to an applied electrical field (e.g.

electrical conductivity or resistance)

Thermal Properties: relates material response to changes in temperature or

temperature gradients across the material (e.g. thermal expansion, heat
capacity)

Magnetic Properties: material response to a magnetic field (e.g. magnetic

susceptibility, magnetization)

Optical properties: material response to electromagnetic or light radiation

stimuli. (e.g. index of refraction and reflectivity)

Deterioration: refers to chemical reactivity of material (e.g. corrosion

resistance)
©McGraw-Hill Education
Why the Study of Materials is Important?
Products (cars, planes, etc.) are made of materials
Production and processing of materials constitute a large part of
our economy
Engineers choose materials to fit a specific product or a specific
application
New materials might be needed for some new applications -
example NASA’s X-planes
• Needs advanced alloys for engine environment
(metals and ceramics)
• Needs lighter materials to be weight less (composites)
• Needs stronger materials to be safe, (composites)
• Needs corrosion resistant materials
• Needs advanced electronics, (electronic materials)
• Needs comfortable and aesthetic airline seat and
other furniture (polymers)
NASA
 Discussion
Why aren’t cars made of glass?
What are the ideal materials to make the body
of a car and wheels? Why?

©McGraw-Hill Education
 Classification of Materials
LOs
o LO4: Classify materials based on their atomic structure.

o LO5: Acknowledge composite and advanced material categories.

©McGraw-Hill Education
 Classes of Materials 1

Three main or fundamental classes (volume)

• Metals
• Example:- Iron, Copper, Aluminum.
• Ceramics
• Example:- Silicon carbide, Alumina, Clay.
• Polymers
• Example:- Polyethylene, Polyvinyl Chloride.

Two processing or application classes (application)

• Composite Materials
• Example:- Fiberglass, Graphite Epoxy, Wood.
• Electronic Materials
• Example:- Silicon, Gallium, Boron.
 Classes of Materials 2

Metals
• Inorganic
• Composed of one or more metallic elements (Fe, Al, Cu, …)
• May contain nonmetals (C, N, Si, …)
• Possess a crystal structure in solid form
• Good to excellent thermal and electrical conductors.
• Are strong and stiff at room temp
• Some are strong at high temperatures
• Generally possess high density
• Can be shaped or cast into different shapes – are malleable
• Some metals are very hard (difficult to indent)
• Are chemically active (form oxides and corrode)
 Classes of Materials 3

Metals, continued
• Two major classes: Ferrous and Non-Ferrous
• Ferrous alloys contain iron as the major element – cast iron, steel
• Non-Ferrous alloys contain little or no iron – aluminum alloys

Nickel- based super

alloys, a non-ferrous
alloy, used in turbine
edgings

The distinction is made because of the significantly higher usage

and production of steels and cast irons when compared to other
alloys.
(a) ©SteveMann/123RF; (b) ©MISS KANITHAR AIUMLA-OR/Shutterstock
 Types of Materials 3

Ceramic Materials
• Inorganic
• Consist of metallic and nonmetallic
elements, chemically bonded together
Ceramic bearings
• Can be either crystalline (alumina) or non-
crystalline (clay)
• Possess, high hardness and strength
• Are highly wear resistant & Low friction
materials
• Very good to excellent insulators of heat
and electricity
• High melting temperature, refractory.
Variety of ceramic parts
(top photo) ©Editorial Image, LLC/Alamy; (bottom photo) Courtesy of Kyocera Industrial Ceramics Corp.
 Types of Materials 1

Polymers
• Organic (carbon is the main building block)
• Most are Synthetic (man made)
• Generally non crystalline (some are semi-crystalline)
• Composed of long molecular chains or networks
• Poor thermal and electrical conductors; good electrical
insulators
• In general, not very strong (not good for high-load bearing)
• Low melt or decomposition temperature
• Generally possess low density
• Can be formed into different shapes
• Are chemically stable
(a) ©PhotoDisc/Getty Images; (b) ©THIERRY ZOCCOLAN/AFP/Getty Images
 Types of Materials 2

Polymers, continued
• Two major classes: Plastics and Elastomers
• Plastics are polymers that can be molded and shaped into different
forms while soft and have good but limited deformability when set
into a solid form
• Plastics may be either a thermoplastic (can be reheated or reshaped)
or a thermoset (can not be reheated and reshaped)
• Elastomers are polymers that have outstanding elastic properties, can
elongate significantly and return to original shape

Polycarbonate,
the materials for Rubber, the
a common CD is material for tyre
a thermoplastic is an elastomer

(a) ©PhotoDisc/Getty Images; (b) ©THIERRY ZOCCOLAN/AFP/Getty Images

 Types of Materials 4

Composite Materials
• A mixture of two or more materials (phases or constituents)
integrated to form a new one.
• Consists of a reinforcing filler material and a binding material.
• The constituents only bond, will not dissolve in each other;
there is a clear interface.
• The constituents keep their original properties
• Mainly two types :-
• Fibrous: Fibers in a matrix
• Particulate: Particles in a matrix
Examples :-
• Fiber Glass ( glass fiber in epoxy matrix)
• Concrete ( Gravels or steel rods in
cement and sand)
Advanced Composites, May/June 1988, p. 53.
 Types of Materials 5

ADVANCED MATERIALS
Electronic Materials
• Possess intermediate properties between electrical conductors and
insulators
• Silicon (intrinsic semiconductor) is a common electronic material.
• Compound semiconductors: consist of 2 or more elements
Gallium Arsenide

Applications :-
• Computer electronics,
Integrated Circuits,
Satellite electronics, etc.

©IMP/Alamy RF
 Cont…
Biomaterials
o Materials used for medical purposes and are
engineered to function in a reliable and safe
manner while interacting with living tissues
(biological system).
o Must be biocompatible, compatible with body
tissues and fluid they interact with
o Non-toxic
o Mimic the body part replaced (properties and
functionality)
o Application examples: hip or knee replacement,
heart valve replacement, dental restoration
o Material commonly used: Metals & Alloys (e.g,
Titanium, Titanium alloys), Ceramics (e.g. https://www.pravhakar.com.np/2022/07/common-
biomaterials-question.html
Alumina), Polymers (e.g., Collagen, starch,
gelatin) , and Composite Materials (Ti-based
composites

©McGraw-Hill Education
 Cont…
Smart Materials
o Senses changes in the environment and responds to the
changes
o Composed of sensors (detects input signal) and actuators
(performs a responsive and adaptive function)
Example: Shape memory alloy

©McGraw-Hill Education https://www.comsol.com/blogs/the-elephants-of-materials-science-smas-never-forget-their-shape/

 Recent Advances and Future Trends 2

Nano materials
• Materials that have a characteristic length scale (particle
diameter, grain size, layer thickness, etc.) that is smaller than
100 nm
• Examples:- Carbon nanotubes, nanoscale graphite (bottom middle
image)

Various nanomaterials with nano scale features or length scales.

Nature.com
 Case Study – Material Selection
Problem: Select suitable material for
bicycle frame and fork.

©EnVogue_Photo/Alamy