Material Science

Material Science and Engineering

An interdisciplinary field that
addresses the fundamental
relationship between the
Processing, Structure and
Properties of materials and
develops them for the
desired technological
application (Performance).

Stone Age

Using naturally occurring materials with only
changes in shape

Bronze Age

Ability to modify materials by
refining (using heat), chemical
modifications (alloying) and
mechanical deformation (cold
working)

Iron Age

Ability to heat treat at high temperature,
control microstructure at different
length scale and ability to design
specific microstructures for specific
properties

Plastic Age

Discovery of polymers, and the
ability to synthesize and process
polymers.

Silicon Age

Ability to control alloying
accurately, ability to make
thin films

microscopic

Is a type of Inside the material which can be
viewedmthrough a microscope.

Crystalline

are
arranged in a metallike
order

amorphous

are Atoms
arranged in disorder like polymers

processing

is the process of processing material
by either heat or mechanical force.

metals

Consists of metal objects Or maybe a little non-metal mixed
with valence electrons surrounded like 'an electron sea' that
holds the positive charges together
• Properties: good heating and electric power, impermeable
light Strong and tough

Polymer

Consisting of plastic and gesture most of them are
organic. (Organic) Contains carbon, contains
molecules in a chain.
• Properties: good electrical insulation, some types
are heat insulation, high flexibility, light weight, low
strength
• Examples: Plastic, Rubber, PVC, Epoxy

Ceramic

Consists of metals and non-metals (non-metals)
Properties: insulating heat and electricity high
temperature resistant more durable in a toxic
environment than metals and polymers Is strong but
fragile (brittle)

composite

made from two or more distinct constituent materials must not dissolve each other.
Example: Fiberglass
(obtaining the
hardness of glass
fibers mixed with the
flexibility of
polymers), steel fiber
reinforced concrete

semiconductor

has electrical properties in the
middle between the body. Electrical and electrical insulation,
such as pure silicon, which are created in different ways

biomaterials

All types of materials that can be used in biological can be
implanted into the human body to change or replace the
damaged organ.

smart materials

Materials can be aware of changes in the environment
(where they operate).

nanomaterials

Is a small material
diameter not over 100 nm.

Biomimicry

is the imitation of
the models, systems, and elements of nature
for the purpose of solving complex human
problems.

molecular solid

is a solid that consists of atoms or molecules held
together by weak intermolecular forces.

Many solids are of this type.
Soft, low melting point, volatile, electrical insulators, poor thermal
fusion.

2

The distance between oxygens is
approximately _ Angstroms.

covalent bonds

inside the molecules are very strong.
The molecules don't break apart easily. However, the forces
attracting neighbouring molecules to each other are very
weak. It is therefore very easy to separate molecules from
one another: e.g. ammonia

metallic solids

is a solid that consists of
positive metal ions held together by a
surrounding "sea of electrons "(metallic
bonding).

metallic bonding

Atoms in metals are closely packed in crystal structure.
Loosely bounded valence electrons are attracted towards
nucleus of other atoms.
Electrons spread out among atoms forming electronclouds.

ionic solids

is a solid that consists of cations and anions held
together by electrostatic attraction of opposite charges (ionic bond).

• Do not conduct electricity (no free ions or electrons) except when
molten or aqueous (as ions are free to move)
• High melting point and boiling point because of very strong
electrostatic attractions between cations, and anions
• Soluble in polar solvents

Covalent network solid

is a solid that consists of atoms held together
in large networks or chains by covalent bonds.

Very hard, high melting point, poor conductors of heat
and electricity high heats of fusion.

Linear chains

are infinitely long linear chains held
together by van der Waals
Properties:
• Low MP, but longer chains have higher MP than shorter
ones
• Do not conduct electricity
• Soft and flexible

2-D layers

held together by weak van der Waals forces.

3-D covalent network solids

are made of atoms held
together by strong covalent bonds.

space lattice

A IMAGINARY
NETWORK
of lines with atoms at lines
intersection that
representing the
arrangement of atoms

unit cell

is that block of
atoms which REPEATS
itself to form space lattice.

crystal lattice

is the geometric arrangement of
lattice points in a crystal.

simple cubic unit cell

is a cubic cell in which the
lattice points are situated only at the corners.

Single crystal

-Properties vary with
direction: anisotropic.

polycystals

-Properties may/may not
vary with direction.

polymorphism

Two or more distinct crystal structures for the same
material (allotropy/polymorphism)

cartesian coordinate

system is used to locate
atoms.

miller indices

are are used to refer to specific lattice
planes of atoms.
They are reciprocals of the fractional intercepts (with
fractions cleared) that the plane makes with the
crystallographic x,y and z axes of three nonparallel edges
of the cubic unit cell.

Imperfection

deviation from the perfectly ordered arrangement of atoms or ions or molecules in crystal

point defect

deviations from ideal arrangement around a point or an atom in a crystal

line defects

deviations from ideal arrangement in entire row of lattice points

stoichiometric defect

imperfections in the crystals such the ration between the cations and anions remains the same as represented by molecular formula

vacancy defect

there are toms missing in the arrangement

interstitial defect

particles are present in the vacancies

schottky defect

equal number of positive ion and negative ion are missing

frenkel defect

Positive ion missing and places into different position, dislocation defect

impurity defect

defect due to foreign ions

Dislocation

are line defects;
slip between crystal planes result

when dislocations move;

produce permanent (plastic)

deformation.

burgers vector

defines the

magnitude and direction of the

deformation;

edge dislocation

• Occurs when an extra half-plane of atoms is inserted into the crystal.

• The distortion is localized around the line where the half-plane ends.

Screw dislocation

Formed by shearing the crystal so that the atomic planes spiral around a dislocation line (like a screw thread).