MSE 230 Assignment 3 Solutions Fall 2013 1 z 1 0 0 0 1 1 1 1 1 1 0 0 0 1 1 1 1 1 1 1 1 1 1 1 y x 2 1 1 0 Cross product 1 1 0 X 1 1 1 1 1 2 1 1 1 1 3 Plane 100 110 111 200 210 211 220 300 221 d hkl a 2 2 h k l 2 0 15nm h 2 k 2 l2 0 45 nm 2 2 h k l 2 FCC h k l all odd all even 1 2 3 2 5 6 8 9 too large 3 No No Yes Yes No No Yes No 111 h 2 k 2 l2 3 d nm 2 from n 2dsin 0 26 0 225 34 5 40 0 0 16 57 9 200 220 I 10 20 40 30 50 60 2 2 4 a Thermal expansion during heating increases the d spacing between planes of atoms Referring to Bragg s law 2dsin increasing d decreases sin This will cause the xray peaks to shift to slightly lower values of 2 b When T Tm iron melts to form a liquid Tm iron 1538 C Liquids are amorphous no long range order and long range ordering is required to form sharp peaks 3
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