1. 1) Metal wires after cold work are usually sold in markets. Why? Increase yield strength This is called cold work strengthening. Tutorial (2)

2. 2) There are gold, silver and bronze medals in Olympic game? Why isn’t copper used for the medal? What kind of materials are used to make medals?

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4. 4) Why is elastic deformation recoverable? Why is plastic deformation un- recoverable?

5. 5. Figure shows the tensile engineering stress-strain behavior for an aluminum alloy. (a) What is the modulus of elasticity? (b) What is the yield strength at a strain offset of 0.002? (c) What is the tensile strength? (d) What is the approximate ductility in percent elongation?

6. 6. (a) List the three classification of steels; (b) for each, briefly describe the properties and typical application. 7. Cite three reasons why ferrous alloys are used so extensively. (b) Cite three characteristics of ferrous alloys that limit their utilization.