Question I (a) List and briefly explain the four components of the discipline of materials science and engineering in a linear relationship. (b) Using a flowchart, classify engineering materials, indicating the types of polymers. 141 (e) Determine the Miller indices for the directions in the cubic unit cell shown below (Fig. Q1): 181 B D A y Fig. QI (d) BCC lithium has a lattice parameter of 3.5089 x 10-10 m and contains one vacancy per 200-unit cells. If the atomic weight of lithium is 207.19 g/mol and Avogadro's number is 6.02 x 102, Calculate: Question 2 (i) the number of vacancies per cubic metre and (ii) the density of lithium. (a) For a HCP crystal structure, show that the ideal c/a ratio is 1.633 [8] [3] [4] (b) Rhenium has an HCP structure, an atomic radius of 0.137 nm, and a c/a ratio of 1.615. Find the volume of the unit cell for Rhenium, if the base area of an HCP crystal structure is 6R²√3 [7] (c) The weights of the individual constituents of an alloy are 45,224 g of copper, 46,267 g of zinc and 953 g of lead. Find the composition, in atomic percent, of the alloy, if the alloy contains no other alloying elements. [Atomic weight of copper = 63.55 g/mol; atomic weight of zinc 65.41 g/mol; atomic weight of lead = 207.2 g/mol; Avogadro's number 6.023 x 1023 atoms/mol]. [5] (d) A cylindrical rod of copper having a yield strength of 240 MPa is to be subjected to a load of 6660 N. If the length of the rod is 380 mm, find the necessary diameter to allow an elongation of 0.5 mm. [E 110 GPa]. [5] Question 3 3