Risbud Sample Final Fall 2007

# Risbud Sample Final - E 45 Practice Problems/SAMPLE FINAL EXAM Problem 1 Using an appropriate sketch derive the radius ratio r/R for a coordination

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E 45 : Practice Problems/SAMPLE FINAL EXAM Problem 1 Using an appropriate sketch, derive the radius ratio r/R for a coordination number of 4. Problem 2 A metal (atomic radius = R) transforms from a BCC structure to a FCC structure. Using your understanding of the relationships between lattice constant “a” and the atomic radius R and the density, volume and number of atoms per unit cell find the percent density change due to this transformation. Problem 3 A piece of 0.2 wt% carbon steel is decarburized by placing it in a high vacuum furnace at 1000 C for an hour. Calculate the carbon concentration at a depth of 480 micrometers below the surface after this 1 hour decarburization at 1000 C using the error function solution to Fick’s Second Law. Given the diffusivity of carbon in this steel at 1000 C to be 1.11 x 10 -11 m 2 /sec. Error Function Values z 0 0.2 0.4 0.477 0.6 0.8 1.0 1.2 1.4 1.6 erf (z) 0 0.2227 0.42839 0.50006 0.60386 0.74210 0.84270 0.9103 0.9523 0.9763 Problem 4a A solid ceramic component weighs 500 grams and has an overall composition of 60 wt % Al 2 O 3 - 40 wt % SiO 2 . It is heated during service to 1600 C, a temperature that is usually maintained for several hours to days (assume equilibrium phases form at 1600 C under these conditions). From the stable phase diagram find:

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## This note was uploaded on 06/05/2008 for the course ANT 2 taught by Professor Smith during the Spring '07 term at UC Davis.

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Risbud Sample Final - E 45 Practice Problems/SAMPLE FINAL EXAM Problem 1 Using an appropriate sketch derive the radius ratio r/R for a coordination

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