Sketch the following planes within a cubic unit cell (provide the steps followed and mark the selected origin). (0 1̅ 1 ) (1 1 2̅ ) (0 1 3̅ )

1. The following questions concern two hypothetical materials, R for the red curve and B for the blue curve, (see figure below) showing the net interatomic forces as a function of interatomic separation. (6") a) Which material will have a higher modulus of elasticity, and why? b) Which material will have a higher melting point, and why? c) Which material will have a larger coefficient of thermal expansion, and why? Hint: You can integrate graphically. ro Separation Force

3.35

2- Question 2. Sketch the [1123] direction in the hexagonal unit cell shown below. a 3