1. Properties of engineering materials

2. materials Metals (ferrous and non ferrous) Ceramics Polymers
Composites
Advanced (biomaterials, semi conductors)

3. Properties Optical Electrical Thermal Mechanical Magnetic
Deteriorative

4. The Structure of Crystalline Solids
- Crystalline : atoms/ crystals
Non crystalline or amorphous
Solidification?

5. Packing of crystals: Non dense =random Dense = regular

6. Unit cell and lattice parameters
Unit cell : small repeated entities
It is the basic structural unit or building block of the crystal structure
Its geometry is defined in terms of 6 lattice parameters:
3 edges length (a, b, c)
3 interaxial angles

7. Unit cell parameters

9. Metallic crystals 3 crystal structures: Face-Centered Cubic FCC
Body-Centered Cubic BCC
Hexagonal close-packed HCP
Characterization of Crystal structure:
Number of atoms per unit cell
Coordination number (Number of nearest neighbor or touching atoms)
Atomic Packing Factor (APF) : what fraction of the cube is occupied by the atoms

10. The Body-Centered Cubic Crystal Structure
Coordination no. = ?
Number of atoms per unit cell = ? ?
what fraction of the cube is occupied by the atoms or Atomic packing factor

11. The Body-Centered Cubic Crystal Structure

12. APF = 0.68 solve ? Relation between r and a

13. Solution

14. The Face-Centered Cubic Crystal Structure
Coordination no. = ?
Number of atoms per unit cell = ? ?
what fraction of the cube is occupied by the atoms or Atomic packing factor

15. The Face-Centered Cubic Crystal Structure

16. APF = 0.74 solve ? Relation between r and a

17. Solution

18. The Hexagonal Close-Packed Crystal Structure

19. HCP
The coordination number and APF for HCP crystal structure are same as for FCC: 12 and 0.74, respectively.
HCP metal includes: cadmium, magnesium, titanium, and zinc.

20. Examples

21. Polymorphism

22. Crystallographic Points, Directions, and Planes

23. POINT COORDINATES
Point position specified in terms of its coordinates as fractional multiples of the unit cell edge lengths
( i.e., in terms of a b and c)
0,0,0 Z Y X
1,1,1

24. Solve point coordinates (2,3,5,9)

25. solution

26. Crystallographic directions
1- A vector of convenient length is positioned such that it passes through the origin of the coordinate system. Any vector may be translated throughout the crystal lattice without alteration, if parallelism is maintained. 2. The length of the vector projection on each of the three axes is determined; these are measured in terms of the unit cell dimensions a, b, and c. 3. These three numbers are multiplied or divided by a common factor to reduce them to the smallest integer. 4. The three indices, not separated by commas, are enclosed as [uvw]. The u, v, and w integers correspond to the reduced projections along x, y, and z axes, respectively.

27. Example

28. Solution

29. Z Y X
[0 1 0]
[1 0 1]

30. Planes ( miller indices)
1- If the plane passes through the selected origin, either another parallel plane
must be constructed within the unit cell by an appropriate translation, or a
new origin must be established at the corner of another unit cell.
2. At this point the crystallographic plane either intersects or parallels each of
the three axes; the length of the planar intercept for each axis is determined
in terms of the lattice parameters a, b, and c.
3. The reciprocals of these numbers are taken. A plane that parallels an axis
may be considered to have an infinite intercept, and, therefore, a zero index.
4. If necessary, these three numbers are changed to the set of smallest integers
by multiplication or division by a common factor.
5. Finally, the integer indices, not separated by commas, are enclosed within
parentheses, thus: (hkl).

31. example

32. Solution

33. Example : solve Z Y X

34. solve z x y a b c z x y a b c

35. Crystallographic Planesz x y a b c
example
a b c
Intercepts 
Reciprocals
1/ / /
Reduction
Miller Indices (110)
example
a b c z x y a b c
Intercepts
1/  
Reciprocals
1/½ 1/ 1/
Reduction
Miller Indices (100)

36. Crystallographic Planesz x y a b c
example
a b c
Intercepts
1/ /4
Reciprocals
1/½ 1/ /¾ /3
Reduction
Miller Indices (634)