(Solved): (a) Explain the difference between allotropy and polymorphism. Give a few examples of allotropes fo ...

(a) Explain the difference between allotropy and polymorphism. Give a few examples of allotropes for carbon. (4 marks) (b) Dislocations in metals have a significant importance in materials science. Explain what are dislocations, draw a simple example to illustrate your answer. (5 marks) (c) What implications do dislocations have on the properties of a metal? (4 marks) (d) Sketch the typical stress-strain behavior of a ductile material upon tensile testing labelling the important zones. How would the stress-strain curve of a brittle material differ from that of a ductile material? (6 marks) (e) Differentiate between fatigue testing and impact testing. What does each simulate in the service life of an engineering component? (4 marks) (f) What does a material's hardness represent in terms of the material's properties? (2 marks)