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Chapter 1 - 1
Palestine Polytechnic UniversityDepartment of Mechanical Engineering
ME251: Materials Science
Course Objective:Introduce fundamental concepts in Materials Science
Syllabus Link: http://cet.ppu.edu/depts/me/metemplate/syllabus/maher_s/Material%20Sc%20SYLLABUS.htm
You will learn about:• material structure
• how structure dictates properties
• how processing can change structure
This course will help you to:• use materials properly – material selection
• realize new design opportunities with materials
Lecturer: Dr. Maher Al-Jabari
Chapter 1 - 2
Concept of Material Science and Engineering
Processing
Structure Properties
level Types
Chapter 1 - 3
COURSE OUTLINE AND CALENDERTOPICS WEEKS/HOURS
Introduction to Materials Science (Chapter 1) 1st / 2+
Atomic Structure & Interatomic Bonding (Chapter 2) 2nd / 2+
The Structure of Crystalline Solids (Chapter. 3) 3rd -5th / 8
Short Exam 1 5th / 1
Imperfections in Crystals (Chapter 4) 6th -7th / 4
Diffusion (Chapter 5) -7th / 2
Mechanical Properties of Metals (Chapter 6) 8th -9th / 6
Phase Diagrams (Chapter 9) 10th -12th /9
Midterm Exam 13th/1
Phase Transformation in Metals (Chapter 10) 13th /2
Heat treatment of metals (Chapter 11) 14th/3
Short Exam 2 15th/1
Introduction to other materials (Polymers and Ceramics - as time permit)
15th- rest
Final Exam University Schedule
Chapter 1 - 4
COURSE POLICIES
GRADING SYSTEM
Short Exam-1 10 %
Midterm Exam 30 %
Short Exam-2 10 %
Quizzes and Attendance 10 %
Final Exam 40 %
Students are required to attend all classes
Unexcused absence of exams is not accepted
Make-up exams are expected to be harder.
Chapter 1 - 5
Chapter 1 - Introduction
• What is materials science / engineering ? • Why should we know about it?
• Materials drive our society ??????? • History
– Stone Age– Bronze Age– Iron Age– Now?
• Silicon Age?• Polymer Age?
Chapter 1 - 6
Introduction
Structure / Levels: Subatomic (e.g. electron, protons) Atomic (atoms and molecules)Microscopic (grains: large groups)macroscopic (by eye)
Property: Response to a specified imposed stimulus Kind and magnitude
Processing: Example Heat Treatment
Applications: ?
Chapter 1 - 7
Example – Biomedical - Hip Implant
• Requirements– mechanical strength
(many cycles)– good lubricity– biocompatibility
Femoral Stem
Ball
AcetabularCup and Liner
Chapter 1 - 8
Other Applications
• Industry • Metal manufacturing • Dentists ?• Think of Others• In Hebron ?• In History ?• In Future ?
Chapter 1 - 9
Developments of New Types of Polymers
• Commodity plastics Ex. Polyethylene
PolypropylenePolystyreneetc.
• Engineering Resins Ex. Polycarbonate
NylonPolysulfoneetc.
Can polypropylene be “upgraded” to properties (and price) near those of engineering resins?
Chapter 1 - 10
ex: hardness vs structure of steel • Properties depend on structure
ex: structure vs cooling rate of steel • Processing can change structure
Structure, Processing, & Properties
Har
dnes
s (B
HN
)
Cooling Rate (ºC/s)
100
200
300
400
500
600
0.01 0.1 1 10 100 1000
(d)
30 m(c)
4 m
(b)
30 m
(a)
30 m
Just Keep in Mind to the end !
Chapter 1 - 11
Types of Materials• Metals: Metallic bonding
– Strong, ductile– high thermal & electrical conductivity– opaque, reflective.
• Polymers/plastics: Covalent bonding sharing of e’s– Soft, ductile, low strength, low density– thermal & electrical insulators– Optically translucent or transparent.
• Ceramics: Ionic bonding (refractory) – compounds of metallic & non-metallic elements (oxides, carbides, nitrides, sulfides)– Brittle, glassy, elastic– non-conducting (insulators)
• Others:• Composite Materials ?• Semi-conductors ?
Chapter 1 - 12
1. Pick Application Determine required Properties
2. Properties Identify candidate Material(s)
3. Material Identify required Processing
Processing: changes structure and overall shapeex: casting, vapor deposition, forming, joining, quenching, annealing.
Properties: mechanical, electrical, thermal,magnetic, optical, deteriorative.
Material: structure, composition.
The Materials Selection Process
Chapter 1 - 13
Properties
• THERMAL• ELECTRICAL• MAGNETIC• OPTICAL
Chapter 1 - 14
THERMAL
• Space Shuttle Tiles: - Silica fiber insulation offers low heat conduction.
• Thermal Conductivity of Copper: -It decreases when you add zinc!
Composition (wt% Zinc)
The
rmal
Con
duct
ivity
(W
/m-K
)
400
300
200
100
00 10 20 30 40
Chapter 1 - 15
ELECTRICAL• Electrical Resistivity of Copper:
• Adding “impurity” atoms to Cu increases resistivity.• Deforming Cu increases resistivity.
Adapted from Fig. 18.8, Callister 7e.(Fig. 18.8 adapted from: J.O. Linde,Ann Physik 5, 219 (1932); andC.A. Wert and R.M. Thomson,Physics of Solids, 2nd edition,McGraw-Hill Company, New York,1970.)
T (°C)-200 -100 0
Cu + 3.32 at%Ni
Cu + 2.16 at%Ni
deformed Cu + 1.12 at%Ni
1
2
3
4
5
6
Res
istiv
ity,
(10-8
Oh
m-m
)
0
Cu + 1.12 at%Ni
“Pure” Cu
Chapter 1 - 16
MAGNETIC• Magnetic Permeability vs. Composition: --Adding 3 atomic % Si makes Fe a better recording medium!
• Magnetic Storage: --Recording medium is magnetized by recording head.
Magnetic FieldM
ag
net
iza
tion Fe+ 3% Si
Fe
Chapter 1 - 17
• Transmittance: --Aluminum oxide may be transparent, translucent, or opaque depending on the material structure.
single crystalpolycrystal:low porosity
polycrystal:high porosity
OPTICAL
Chapter 1 - 18
• Strength • Fabricability • Corrosion Resistance• Availability • Cost • Appearance
Factors
Material Selection
Chapter 1 - 19
• Use the right material for the job.• Understand the relation between properties, structure, and processing.
• Recognize new design opportunities offered by materials selection.
• Do not forget the triangle:
Course Goals:
SUMMARY
Processing
Structure Properties