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Unformatted text preview: MatSci 201: Introduction to Materials Homework #3: Due Wednesday, October 8, 2008 by 5 PM 60 points total 1. (10 points) (a) Callister, Question 4.2 (b) Just prior to melting (say 1060°C), by how much do the vacancies in gold increase? (b) Substitute new temperature: 1060ºC or 1333 K. Assume density does not change (not the best assumption!) N V = 1.13 X 10 19 cm-3 = 1.13 x 10 25 m-3 or a factor of 3 higher with 160 ° . This is probably a lower bound since the density will be decreasing, too. 2. (10 points) (a) Assuming that there are no iron atom vacancies, find the maximum amount of carbon that could be dissolved interstitially in an FCC arrangement of iron atoms. Take the carbon to only occupy the largest interstitial sites (what you determined in Homework #2). (b) If your answer is different from the experimentally observed value of 2 weight percent, give a possible explanation. In the FCC cell the total number of interstitials = 1 internal + 12 edge sites each have ¼ of its volume in a unit cell. of its volume in a unit cell....
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- Spring '10
- Atom, Chemical bond, Surface energy