Page 167 - Materials Science and Engineering An Introduction

Questions and Problems • 139

FUNDAMENTALS OF ENGINEERING 4.3FE What is the composition, in weight percent, of
QUESTIONS AND PROBLEMS an alloy that consists of 94.1 at% Ag and 5.9 at%
4.1FE Calculate the number of vacancies per cubic Cu? The atomic weights for Ag and Cu are 107.87
meter at 1000 C for a metal that has an energy g/mol and 63.55 g/mol, respectively.
for vacancy formation of 1.22 eV/atom, a density (A) 9.6 wt% Ag and 90.4 wt% Cu
3
of 6.25 g/cm , and an atomic weight of 37.4 g/mol. (B) 3.6 wt% Ag and 96.4 wt% Cu
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(A) 1.49 10 m 3 (C) 90.4 wt% Ag and 9.6 wt% Cu
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(B) 7.18 10 m 3 (D) 96.4 wt% Ag and 3.6 wt% Cu
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(C) 1.49 10 m 3
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(D) 2.57 10 m 3
4.2FE What is the composition, in atom percent, of an
alloy that consists of 4.5 wt% Pb and 95.5 wt% Sn?
The atomic weights for Pb and Sn are 207.19 g/mol
and 118.71 g/mol, respectively.
(A) 2.6 at% Pb and 97.4 at% Sn
(B) 7.6 at% Pb and 92.4 at% Sn
(C) 97.4 at% Pb and 2.6 at% Sn
(D) 92.4 at% Pb and 7.6 at% Sn