METALLIC MATERIALS

YOUR AIMS

On completion of this lesson you should be able to:

- discuss the basic structure of metals
- appreciate the types of defect that may arise in the crystalline structure of metals
- understand the significance of defects in crystallinity with regard to the properties of metals
- examine the possible interactions when a different type of atom is introduced into a pure metal.

SELF-ASSESSMENT QUESTIONS

1. What is the total number of Bravais lattice types?

2. For the two-dimensional lattice shown below, determine the following:
(i) the number of nearest neighbours
(ii) the unit cell.

3. Sketch the following unit cells and for each case give one example of a metal which adopts that structure:
(i) f.c.c.
(ii) b.c.c.
(iii) h.c.p.

4. Describe the relevance of each of the following defects to the properties of metals:
(i) grain boundary
(ii) dislocation
(iii) vacancy.

5. Explain what is meant by an alloy.

6. Describe each of the following metal constituents.

7. Explain what is meant by a superlattice.