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Unformatted text preview: MAE 20 June 30, 2010 Homework 1 Due on Wednesday (July 7), at the beginning of class Total: 60 points Clearly show the detailed steps in your solutions. (a) Even though the bonding energies for a ceramic, say MgO, ~ 1000 kJ/mole is larger than that of diamond (~ 700 kJ/mole) why are ceramics more brittle? (3 pts) (b) Give two examples where secondary bonding (van der Waals bonding) is observed? (3 pts) (c) What is the bonding type in diamond? Discuss a property that is commensurate with its bonding? (3 pts) (d) What type(s) of bonding would be expected for: (i) brass, (ii) rubber, (iii) GaAs, (iv) solid xenon, (v) bronze, (vi) Nylon (6 pts) (e) Would you expect MgO or Mg to have higher strength? Why? (3 pts ) (f) Sketch the following directions in a cubic unit cell: (i)  (ii) [0 , (iii) [ 2 , (iv)  (4X 2=8pts) (g) Determine the Miller indices for the four planes shown in the following unit cells: (4X 2= 8 pts) (h) Indicate all the directions of the form <110> that lie in the ( 1 plane, of a cubic unit cell (5 pts) (i) What is the atomic packing fraction? Show that the atomic packing fraction for a body-centered cubic (bcc) crystal is 0.68 (or 68%) (5 pts) (j) Fe has a bcc crystal structure, with an atomic radius of 0.124 nm and an atomic weight of 55.85 g/mole....
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This note was uploaded on 09/22/2010 for the course MAE MAE20 taught by Professor Mae20 during the Spring '10 term at UCSD.
- Spring '10