ENG 2002 Lecture Notes - Jmol, Linear Interpolation, Carburizing
2 Apr 2014
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Problem solutions: calculate the fraction of atom sites that are vacant for lead at its melting temperature of 327 c (600 k). Assume an energy for vacancy formation of 0. 55 ev/atom. In order to compute the fraction of atom sites that are vacant in lead at 600 k, we must employ equation. As stated in the problem, qv = 0. 55 ev/atom. 0. 55 ev/atom (8. 62 10 5 ev/atom- k) (600 k) = 2. 41 10-5: calculate the activation energy for vacancy formation in aluminum, given that the equilibrium number of vacancies at 500 c (773 k) is 7. 57 1023 m-3. The atomic weight and density (at 500 c) for aluminum are, respectively, 26. 98 g/mol and 2. 62 g/cm3. Upon examination of equation 4. 1, all parameters besides qv are given except n, the total number of atomic sites. However, n is related to the density, ( al), avogadro"s number (na), and the atomic weight (aal) according to equation 4. 2 as.
