Pharos University
Faculty of Engineering
Petrochemical Department
Lecturer: Dr.Ehssan Nassef
Material Science (PE217)
Fall (2012-2013)
Revision on the definitions from lecture (2) to lecture (11)
1. CERAMICS:
CERAMICS are compounds between metallic and nonmetallic
elements.
2. COMPOSITES:
 A number of composite materials have been engineered that
consist of more than one material type.
3. ADVANCED MATERIALS:
 Materials that are utilized in high-technology (or high-tech)
applications are sometimes termed advanced materials.
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4. Atom:
 Each atom consists of a very small nucleus composed of protons
and neutrons, which is encircled by moving electrons.
 Atomic number (Z):
 Is the number of protons in the nucleus
atomic weight;
 of an element corresponds to the weighted average of the
atomic masses of the atom’s.
 Crystalline:
 A crystalline material is one in which the atoms are situated in
a repeating or periodic array over large atomic distances.
 Crystal structure:
 Some of the properties of crystalline solids depend on the
crystal structure of the material, the manner in which atoms,
ions, or molecules are spatially arranged.
 Lattice: lattice is used in the context of crystal structures; in
this sense ‘‘lattice’’ means a three-dimensional array of points
coinciding with atom positions (or sphere centers).
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 UNIT CELLS: The atomic order in crystalline solids indicates
that small groups of atoms form a repetitive pattern.
 The coordination number:
 For metals, each atom has the same number of nearestneighbor or touching atoms, which is the coordination
number.
 The atomic packing factor (APF)

Answer the following questions:
 Define stress –strain relation.
 State Hooke’s law.
 Modules of elasticity.
 Tensile strength ,percent elongation ,Ductility.
 Hardness and the different tests methods for measuring it.
 Brittle fracture ductile fracture.
 Fatigue.
 Elastic deformation and plastic deformation
 Substitutional and interstational impurities atoms.
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 Types of ceramics crystal structure.
 Defects in ceramics:
Frenkel Defect:a cation is out of place.
Shottky Defect
a paired set of cation and anion vacancies.
• Polymer:
The term polymer denotes a molecule made up by the repetition
of smaller molecules, the monomer.
 Thermo plastic polymers:
Thermosetting polymers are network polymers.They become
permanently hard during their formation, and do not soften upon
heating.
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STRESS–STRAIN BEHAVIOR of polymers
Composite
 Is considered to be any multiphase material that exhibits a
significant proportion of the properties of both constituent
phases such that a better combination of properties is realized.
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Many composite materials are composed of just two phases; one is
termed the. Matrix, which is continuous and surrounds the other
phase, often called the dispersed phase.
 Corrosion in metals: is defined as the destructive and
unintentional attack of a metal; it is electrochemical and
ordinarily begins at the surface.
 An oxidation reaction:

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B-In basic or neutral medium:
O2+2H2O+4e-
4(OH)-
 Corrosion in ceramics
 Corrosion in polymers(Degradation)
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