Material science

1. Material Science
Eng. Kareem. H. Mokhtar

2. Important notes
 Make sure to submit your work BEFORE the Due date
 50% minus if you submit after it.

3. Assignments
You will get your feed back
After submitting your
assignment and you should:
1- submit before the due date
2- solve all the questions
3- submit your assignment as
neat as possible

4. Quizzes
1- Quizzes will start at a certain time
2- You are not allowed to flip your
quiz until you hear that the quiz will
start now.
3- When you hear put your pens
down, stop answering immediately.
4- Follow the instructor’s directions
Never Cheat !!

5. Report and a presentation
 Form groups of ”2”
 Be on time
 Stick to the time limit

7. Classification
Material can be divided into
1- Crystalline material
These materials contains one or more crystal, In each crystall atoms
show a periodic arrangement.
2- Non- crytalline material (amorphous material)
These materials does not contain a periodic arrangement of ions or
atoms

8. Basic Concepts
 Deformation
 Elastic Deformation
 Plastic Deformation
 Stress
 Strain

9. Deformation
 It is the changes in an object's shape due to the application of a force or several
forces

10. Types of Deformation
 Deformation can be classified into two groups
 1- Elastic deformation
 It is a reversible deformation, which means the body will return to it’s original
shape when the stress is removed
 2- Plastic Deformation
 It is an irreversible deformation (permanent)

11. Stress
 It is the force applied per area of the body
 Different forms of stresses will be discussed later
= F
A
stress

12. Strain

13. Mechanical Properties
 A- Elasticity
 B-Ductility
 C- strength
 D- Hardness
 E- Brittleness
 F-Toughness

14. Elasticity
 Elastic material: material that springs back to its original
shape after the removal of the stress

15. Ductility
 It is the ability of the material to bend or stretch without breaking

16. Brittleness
 The material is said to be brittle if it fails without any plastic deformation
 A- ductile material
 B- moderately ductile
material
 C- Brittle material

17. Hardness
 It is the resistance of the material to scratch or penetration

18. Stress- Strain curve
TS
stress
strain

19. Stress-strain curve
stress
strain
P
P : Proportional limit
E
E : Elasticity limit
Y : Yield point
U
U: Ultimate tensile strength
B: Break point
B
Elastic Plastic
Y

20. Stress-strain curve
 Elasticity limit :
 is the maximum stress within a material can withstand before permanent deformation.
 This point is the limit of the elastic region
 Yield point:
 marks the beginning of plasticity.
 Ultimate tensile strength:
 The maximum stress that a material can withstand while being stretched or pulled before
breaking

21. Toughness
 It is the energy absorbed by the material before fracture
 It is the total area under the curve for the stress-strain up to fracture