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1.
0 INTRODUCTION
• Historical perspective
Stone Bronze Iron Advanced Materials
• What is Material Science and Engineering?

Processing Structure Properties Performance
• Classification of Materials
Metals, Ceramics, Polymers, Semiconductors, etc
1.1 Historical Perspective
Our daily lives are influenced by materials: Housing,
transporting, clothing, communication, food, etc
 Historically, the advancement of societies is liked
to members’ ability to produce and manipulate
materials to fill their needs (i.e level of materials
development).
 Beginning of Material Science: People began to

make tools from stone – Start of Stone age about 2
Million years.
Natural materials: stone, wood, clay, skin, etc
 The stone age ended about 5000 years ago
with the introduction of Bronze in the far east.
Bronze is an alloy (a metal made up of more than
1 element),
copper + < 25% of tin + other elements
Bronze: can be hammered or cast into variety of

shapes, can be made harder by alloying, corrodes
slowly after a surface oxide film forms.
 The Iron Age: It began about 3000 years ago and it
continues till today.
Use of iron and steel, a stronger and cheaper
material drastically changed the life of a common
person.
 Age of Advance Materials: New types materials

have been introduced (ceramic, semiconductors,
polymers, etc).
1.2 What is Material Science and Engineering?
Material Science is the investigation of the
relationship between the structures and properties
of materials.
1.2.1 Material structure: relates to the arrangement
of its internal components. It can be grouped into:
1. Subatomic structure: Electronic structure of
individual atoms that defines interactions among
atoms (interatomic bonds).
2. Atomic level: Structure comprises of arrangement
of atoms in materials (for some atoms can have
different properties e.g the graphite and diamond
forms of carbon).
3. Microscopic structure: Structure consists of
arrangement of small grain of materials that can be
identified with the microscope.
4. Macroscopic structure:
Structural elements can be
viewed by the naked eye.
1.2.2 Material property
Properties are the ways the materials respond to
environmental and external forces.
Properties can be grouped into 6 categories:
1. Mechanical properties- elastic modulus and
tensile strength
2. Electrical and Magnetic properties- electrical
conductivity, dielectric constant, permitivity, etc
3. Thermal properties- heat capacity, thermal
conductivity, emissivity, flammability, etc
4. Optical properties- refractive index, reflectivity
5. Deteriorative properties- chemical reactivity, pH
Other important components of material science and
engineering are processing and performance.
Processing Structure Properties Performance

1.3 Classification of materials
Materials can be classified according to the way the
atoms are bonded in the materials.
1.3.1 Metals: valence electrons are detached from

the atoms, and spread in electron sea that glues the
ions together.
Properties: Strong, ductile, conduct heat and
electricity well, and are shinny if polished.
1.3.2 Ceramics
Atoms behave like +ve and –ve ions, and are
bonded by Coulomb forces. They are usually a
combination of metals or semiconductors with
oxides, nitrides, and carbides. Eg glass, porcelain.
Properties: Hard, brittle, and insulators.
1.3.3 Polymers
They are bonded by covalent forces and also by
weak Van der Waal forces, and usually based on C
and H. They decompose at mod. temperate (100-
400 oC), and are lightweight. Egs rubber, plastics
1.3.4 Semiconductors
Bonding is covalent. Their electrical properties
depends on minute proportions of contaminants.
Egs Si, Ge, Ga, As.
1.3.5 Composites
Consists of combination of two or more different
materials. A composite is designed to exhibit the
combination of the best characteristics of each of
the component materials. Eg is fiber glass, in which
fiber is embedded in a polymeric material. Fiber
glass acquires strength from glass and flexibility
from the polymer.
1.3.6 Biomaterials
Biomaterials are employed in components implanted
into the human body for replacement of diseased or
damaged body parts.
1.3.7 Smart Materials
Smart (or intelligent) materials have the ability to
sense changes in their environments and then
respond to these changes in predetermined manners.

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• What is Material Science and Engineering?

 Beginning of Material Science: People began to

copper + < 25% of tin + other elements

Bronze: can be hammered or cast into variety of

 Age of Advance Materials: New types materials

Processing Structure Properties Performance

1.3.1 Metals: valence electrons are detached from

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