Palestine polytechnic university department of mechanical engineering me251 materials science
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Palestine Polytechnic University Department of Mechanical Engineering ME251: Materials Science. Lecturer: Dr. Maher Al-Jabari. Course Objective: Introduce fundamental concepts in Materials Science

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Palestine polytechnic university department of mechanical engineering me251 materials science
Palestine Polytechnic UniversityDepartment of Mechanical EngineeringME251: Materials Science

Lecturer: Dr. Maher Al-Jabari

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


Concept of material science and engineering
Concept of Material Science and Engineering

Processing

Structure

Properties

Types

level



Course policies
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 introduction
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?


Introduction
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: ?


Example biomedical hip implant
Example – Biomedical - Hip Implant

  • Requirements

    • mechanical strength (many cycles)

    • good lubricity

    • biocompatibility

Ball

Acetabular

Cup and Liner

Femoral

Stem


Other applications
Other Applications

  • Industry

  • Metal manufacturing

  • Dentists ?

  • Think of Others

  • In Hebron ?

  • In History ?

  • In Future ?


Developments of new types of polymers
Developments of New Types of Polymers

  • Commodity plastics

    Ex. Polyethylene Polypropylene Polystyrene etc.

  • Engineering Resins Ex. Polycarbonate Nylon Polysulfone etc.Can polypropylene be “upgraded” to properties (and price) near those of engineering resins?


Structure processing properties
Structure, Processing, & Properties

(d)

30mm

(c)

(b)

(a)

4mm

30mm

30mm

• Properties depend on structure

ex: hardness vs structure of steel

6

00

5

00

4

00

Hardness (BHN)

3

00

Just Keep in Mind

to the end !

2

00

100

0.01

0.1

1

10

100

1000

Cooling Rate (ºC/s)

• Processing can change structure

ex: structure vs cooling rate of steel


Types of materials
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 ?


The materials selection process
The Materials Selection Process

1.

Pick Application

Determine required Properties

Properties: mechanical, electrical, thermal,

magnetic, optical, deteriorative.

2.

Properties

Identify candidate Material(s)

Material: structure, composition.

3.

Material

Identify required Processing

Processing: changes structure and overall shape

ex: casting, vapor deposition, forming, joining,

quenching, annealing.


Properties
Properties

  • THERMAL

  • ELECTRICAL

  • MAGNETIC

  • OPTICAL


Thermal

400

300

(W/m-K)

200

Thermal Conductivity

100

0

0

10

20

30

40

Composition (wt% Zinc)

THERMAL

• Space Shuttle Tiles:

- Silica fiber insulation

offers lowheat conduction.

• Thermal Conductivity

of Copper:

-It decreases when you add zinc!


Electrical

6

5

Cu + 3.32 at%Ni

4

Cu + 2.16 at%Ni

Resistivity, r

deformed Cu + 1.12 at%Ni

3

(10-8 Ohm-m)

2

Cu + 1.12 at%Ni

1

“Pure” Cu

0

-200

-100

0

T (°C)

ELECTRICAL

• Electrical Resistivity of Copper:

Adapted from Fig. 18.8, Callister 7e.

(Fig. 18.8 adapted from: J.O. Linde,

Ann Physik5, 219 (1932); and

C.A. Wert and R.M. Thomson,

Physics of Solids, 2nd edition,

McGraw-Hill Company, New York,

1970.)

• Adding “impurity” atoms to Cu increases resistivity.

• Deforming Cu increases resistivity.


Magnetic

Fe+ 3% Si

Fe

Magnetization

Magnetic Field

MAGNETIC

• Magnetic Storage:

--Recording medium

is magnetized by

recording head.

• Magnetic Permeability

vs. Composition:

--Adding 3 atomic % Si

makes Fe a better

recording medium!


Optical
OPTICAL

polycrystal:

low porosity

polycrystal:

high porosity

single crystal

• Transmittance:

--Aluminum oxide may be transparent, translucent, or

opaque depending on the material structure.


Material selection
Material Selection

Factors

  • • Strength

  • Fabricability

  • Corrosion Resistance

  • Availability

  • Cost

  • Appearance


Summary
SUMMARY

Course Goals:

• 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:

Processing

Structure

Properties