1. Materials science is the study of relationships between the structure and properties of materials. It relates how the atomic and molecular structure of a material influences its properties. 2. A material's properties determine how it responds to external forces and the environment. Key properties include mechanical, electrical, thermal, optical, and chemical properties. Mechanical properties describe response to forces like strength and toughness. 3. There are three main classes of materials: metals, ceramics, and polymers. Metals are strong, ductile, and conductive. Ceramics are brittle but heat resistant. Polymers are lightweight and insulating. Materials science helps understand materials and design new components.

1. MATERIALS SCIENCE
MENJANA MINDA KREATIF DAN INOVATIF

2. Introduction
What is materials science ?
Relationship between structures and properties of
materials
Relates to the arrangements
of electrons surrounding of
the atom which influence the
+ Cr
atomic bonding
Examples
1. Fe
+C
Heat Treatment
SiC particles
2. Al + Si
+ Heat treatment
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3. Introduction
Properties are the way the material responds to the
environment and external forces
Mechanical Properties
Electrical & Magnetic
Properties
Response to mechanical forces,
strength, etc
Response to electrical and magnetic
fields, conductivity, etc
Thermal Properties
Related to transmission of heat and
heat capacity
Optical Properties
Include to absorption, transmission
and scattering of light
Chemical Properties
In contact with the environment eg :
corrosion resistance
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4. Introduction
Properties are the way the material responds to
the environment and external forces
Mechanical Properties :
Response to mechanical forces, such as
Strength (……….)
Toughness
Hardness
Ductility
Elasticity, Fatigue, Creep…etc
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5. Introduction
Why study Materials Science ?
1
Important to understand capabilities and limitation
of materials
Lack of fundamental understanding of materials
and their properties will cause catastrophic failure
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6. Introduction
2 An understanding of Materials Science helps us to design
better components, parts , devices, etc.
How do you make something stronger or lighter?
How do elements come together to form alloys ?
Why ……..
3 It is interesting and helps to make you more informed person
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7. Introduction
There are 3 major classes
1. Metal
Strong, ductile, High thermal & electrical conductivity, Opaque, reflective
Pure metallic elements or combination of metallic elements (alloys) .
Air frame, landing gear, engine components
2. Ceramic
Brittle, glassy, elastic, Non-conducting (insulators)
Molecules based on bonding between metallic and non-metallic elements.
Typically insulating and refractory – coating on high temp engine
components
3. Polymers
Ductile, low strength, low density, Thermal & electrical insulators
Optically translucent or transparent
Many are organic compound Chemically based on C , H other non-metals
– windows , cabin interior
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8. Introduction
Sub-classes of Materials
i. Semiconductor (ceramics), Intermediate electrical properties
ii. Composite (all three classes), combination
iii. Bio Materials (all three classes), Compatible with body tissue
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9. Introduction
Engineering Materials
Metals
Ferrous
Non-Metals
Non ferrous
Ceramics
Aluminium
Glass
Thermoplastics
PMC
Carbon Steel Copper
Graphite
Thermosetting
MMC
Alloy Steel
Titanium
Diamond
Elastomers
CMC
…...
…...
Irons
Polymers
Composites
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10. Introduction
Metal
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11. Introduction
CERAMIC
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12. Introduction
POLYMER
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13. Introduction
COMPOSITE
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14. Introduction
SEMICONDUCTOR
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15. Li
Be
Na
Ca
Rb
Sr
Cs
Ba
Fr
inert gases
accept 1e-
He
Mg
K
give up 3e-
H
accept 2e-
THE PERIODIC TABLE
give up 2e-
give up 1e-
Introduction
O
F
Ne
S
Cl
Ar
Sc
Se
Br
Kr
Y
Te
I
Xe
Po
At
Rn
Ra
• Columns: Similar Valence Structure
6
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16. Introduction
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17. Introduction
Metallic
elements
+
+
Non-metallic
elements
Ceramic
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18. Introduction
Polymer
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19. Introduction
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20. . Introduction
Angstrom = 1Å = 1/10,000,000,000 meter = 10-10m
Nanometer = 10nm = 1/1,000,000,000 meter = 10-9m
Micrometer = 1μm = 1/1,000,000 meter = 10-6m
Millimeter = 1mm = 1/1,000 meter = 10-3m
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21. Atomic Structure
Atoms
= nucleus (protons and neutron)
+ electrons
Electrons, protons have negative and
positive charges of the same magnitude
Neutron are electrically neutral
Proton and neutron have the same mass
1.67 x 10 –27 kg
Mass of an electron is much smaller (9.11x
10 –31 kg and can be neglected in
calculation
The atomic mass (A) = mass of proton mass of neutron
Atomic number (Z) = number of proton
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22. Atomic Structure
The atomic mass unit(amu) is often used to express atomic weight.
The number of atom in a mole is called the Avogadro number, (Nav),
Nav = 6.023 x 10 23 Nav = 1 gram/amu
Example :
Atomic weight of iron =55.85 amu/atom = 55.85 g/mol
Valence electrons
Valence electrons – those in unfilled shells
Valence electrons determine all of the following
properties :
Chemical, Electrical, Thermal , Optical
Filled shells more stable
Valence electrons are most available for bonding
and tend to control the chemical properties, etc..
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23. Atomic Bonding
1. Ionic bonding
2. Covalent bonding
Strong interaction among
negative atom (have an extra
electron ) and positive atom
(lost an electron)
Electrons are shared between
the molecules to saturate the
valence
Large interactive force due to
sharing of electrons
Strong atomic bonds due to
transfer of electrons
3. Metallic bonding
The atoms are ionized, loosing some electrons from the valence
band.
Those electrons form a electron sea, which binds the charged
nuclei in place.
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24. Atomic Bonding
1. Ionic Bonding
• Occurs between + and - ions.
• Requires electron transfer.
• Large difference in electronegativity required.
• Example: NaCl
Ionic bond :
Metal
donates
electrons
+
Non-metal
accepts electrons
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25. Atomic Bonding
Ionic bonding in NaCl
3s1
Sodium
Atom
Na
Sodium Ion
Na+
3p6
I
O
N
I
C
Chlorine
Atom
Cl
Chlorine Ion
Cl -
B
O
N
D
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26. Atomic Bonding
EXAMPLES: IONIC BONDING
• Predominant bonding in Ceramics
NaCl
MgO
CaF2
CsCl
H
2.1
Li
1.0
Be
1.5
Na
0.9
Mg
1.2
K
0.8
Ca
1.0
Rb
0.8
Cs
0.7
Fr
0.7
He
-
O
F
3.5 4.0
Cl
3.0
Ne
-
Br
2.8
Kr
-
Sr
1.0
I
2.5
Ba
0.9
At
2.2
Xe
Rn
-
Ra
0.9
Ti
1.5
Cr
1.6
Fe
1.8
Ni
1.8
Zn
1.8
As
2.0
Ar
-
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27. Atomic Bonding
2. Covalent Bonding
Electrons are shared between the molecules to saturate the
valence
Electron
Pair
H
+ H
1s1
Electrons
H H
H
Hydrogen
Molecule
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28. Atomic Bonding
Requires shared electrons
Example : CH4
C : has 4 valence e, needs 4 more
H : has 1 valence e, needs 1 more
Si with electron valense : 4
Four covalent bonds must be formed
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29. Atomic Bonding
EXAMPLES: COVALENT BONDING
H2
H
2.1
Li
1.0
Na
0.9
Ca
1.0
Rb
0.8
Sr
1.0
Cs
0.7
Ba
0.9
Fr
0.7
Ra
0.9
C(diamond)
Be
1.5
Mg
1.2
K
0.8
column IVA
H2O
SiC
Ti
1.5
Cr
1.6
Fe
1.8
F2
He
O
2.0
C
2.5
Si
1.8
Ni
1.8
Zn
1.8
Ga
1.6
Ge
1.8
As
2.0
Sn
1.8
Pb
1.8
F
4.0
Cl
3.0
Ne
-
Br
2.8
Kr
-
I
2.5
Xe
-
At
2.2
Cl2
Rn
-
Ar
-
GaAs
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30. Atomic Bonding
3. Metallic Bonding
Arises from a sea of donated valence
electrons (1, 2, or 3 from each atom).
Primary bond for metals and their alloys
Valence electrons are detached from
atoms, and spread in an electron sea that
“glues’ the ions together
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31. • Pure metals are significantly more malleable than ionic or covalent
networked materials.
• Strength of a pure metal can be significantly increased through
alloying.
• Pure metals are excellent conductors of heat and electricity.
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32. Crystalline Solid
Levels of atomic arrangements in materials
1. Gas
2. Water
3. glass
3. Solid metal or alloy
- crystal
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33. Crystalline Solid
How do atoms arrange themselves to form solid?
Crystalline materials
• atoms pack in periodic, 3D arrays
• typical of:
-metals
-many ceramics
-some polymers
Crystalline SiO2
Non-crystalline materials...
• atoms have no periodic packing
• occurs for:
-complex structures
-rapid cooling
"Amorphous" = Noncrystalline
Non- crystalline SiO2
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34. Crystal Structure
Crystal structure (microstructure) affects the mechanical
properties of materials such as tensile strength, ductility..etc
Crystal structure is describe as:
i.
lattice : a 3-D of point in space. Each point must have identical
surrounding.
ii.
Unit cell : the simplest repeating unit in a lattice
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35. Crystal Structure
Crystal structure : Atoms arranged in
repetitive 3-D pattern, in long range order
(LRO)
Properties of solids depends upon crystal
structure and bonding force.
Space lattice :
An imaginary network of lines,
with atoms at intersection of lines,
representing the arrangement of
• atoms is called.
• Unit cell : block of
atoms which repeats itself
to form space lattice.
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36. Crystal Structure
Assume atoms as being hard spheres with
well-defined radii
a = Lattice parameter or lattice
constant
The unit cell is the smallest
structural unit or building block
than can describe the crystal
structure.
Repeating of the unit cell generates
the entire crystal
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37. Crystal Structure
Unit cell:
Smallest repetitive volume which contains the
complete lattice pattern of a crystal.
7 crystal systems
14 crystal lattices
a, b, and c are the lattice constants
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38. Crystal Structure
Only 7 different types of unit cells are necessary to create all point
lattices.
According to Bravais (1811-1863) 14 standard unit cells can describe
all possible lattice networks
Bravais Lattice : 7 crystal systems give 14 lattice
1. Cubic
2. Tetragonal
3. Hexagonal
4. Orthorombic
5. Rhombohendral
6. Monoclinic
7. Triclinic
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39. Crystal Structure
1. Cubic Unit Cell
 a=b=c
 α = β = γ = 900
ii. Simple
iii. Body Centered
i. Face centered
2. Tetragonal
 a =b ≠ c
 α = β = γ = 900
i. Simple
ii. Body Centered
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40. Crystal Structure
3. Orthorhombic
 a≠ b≠ c
 α = β = γ = 900
iii. Base Centered
i. Face Centered
ii. Simple
iv. Body Centered
4. Rhombohedral
 a =b = c
 α = β = γ ≠ 900
Simple
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41. Crystal Structure
5. Hexagonal
 a≠ b≠ c
 α = β = γ = 900
Simple
6. Monoclinic
 a≠ b≠ c
 α = β = γ = 900
i. Simple
ii. Base Centered
7. Triclinic
 a≠ b≠ c
 α = β = γ = 900
Simple
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42. Crystal Structure
Most of engineering metals have one of the following
crystal structure
i. Body-centered cubic (BCC)
ii. Face-centered cubic (FCC)
iii. Hexagonal close packed (HCP)
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43. FCC
1. Face-Centered Cubic (FCC)
Atoms are located at each of the corners and on the centers of all the
faces of cubic unit cell
Cu, Al, Ag, Au, Pb, Ni, Pt, ….. have this crystal structure
Good ductility
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44. FCC
Number of atoms per unit cell, n = 4
Fraction of volume occupied by hard sphere,
APF = 0.74
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45. BCC
2. Body-Centered Cubic (BCC)
Atom at each corner and at center of cubic unit cell
Cr, Fe-, Mo, Li, W have this crystal structure
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46. BCC
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3a
a
2a
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47. HCP
3. Hexagonal Close-Packed (HCP)
Atom at each corner and at center of unit cell
Be, Cd, Co, Mg, Ti, Zn have this crystal structure
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48. Crystal Structure
APF for a body-centered cubic structure
R
a
3
8.373R

 0.68
3
12.32R
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49. Crystal Structure
APF for a Face-centered cubic
16
R 3
V
 s  3 3
 0.74
Vc
16R 2
APF for a Hexagonal Close-Pack
a
APF
= 0.74
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50. Crystal Structure
THEORETICAL DENSITY,
atoms/unit cell
r  nA
Volume/unit cell VcNA
(cm3/unit cell)
r
Atomic weight (g/mol)
Avogadro's number
(6.023x 1023 atoms/mol)
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51. Crystal Structure
Symbol
Element
Al
Aluminum
Ar
Argon
Ba
Barium
Be
Beryllium
B
Boron
Br
Bromine
Cd
Cadmium
Ca
Calcium
C
Carbon
Cs
Cesium
Cl
Chlorine
Cr
Chromium Co
Cobalt
Cu
Copper
F
Flourine
Ga
Gallium
Ge
Germanium Au
Gold
He
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