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Callister - An introduction - 8th edition

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118 • Chapter 4 / Imperfections in Solids<br />

Important Terms and Concepts<br />

alloy<br />

atomic vibration<br />

atom percent<br />

Boltzmann’s constant<br />

Burgers vector<br />

composition<br />

dislocation line<br />

edge dislocation<br />

grain size<br />

imperfection<br />

interstitial solid solution<br />

microscopy<br />

microstructure<br />

mixed dislocation<br />

photomicrograph<br />

point defect<br />

scanning electron microscope<br />

(SEM)<br />

scanning probe microscope<br />

(SPM)<br />

screw dislocation<br />

self-interstitial<br />

solid solution<br />

solute<br />

solvent<br />

substitutional solid solution<br />

transmission electron<br />

microscope (TEM)<br />

vacancy<br />

weight percent<br />

REFERENCES<br />

ASM Handbook, Vol. 9, Metallography and Microstructures,<br />

ASM International, Materials<br />

Park, OH, 2004.<br />

Brandon, D., and W. D. Kaplan, Microstructural<br />

Characterization of Materials, 2nd <strong>edition</strong>,<br />

Wiley, Hoboken, NJ, 2008.<br />

Clarke, A. R., and C. N. Eberhardt, Microscopy<br />

Techniques for Materials Science, CRC Press,<br />

Boca Raton, FL, 2002.<br />

Kelly,A., G.W. Groves, and P. Kidd, Crystallography<br />

and Crystal Defects, Wiley, Hoboken, NJ, 2000.<br />

Tilley, R. J. D., Defects in Solids, Wiley-Interscience,<br />

Hoboken, NJ, 2009.<br />

Van Bueren, H. G., Imperfections in Crystals, North-<br />

Holland, Amsterdam (Wiley-Interscience, New<br />

York), 1960.<br />

Vander Voort, G. F., Metallography, Principles and<br />

Practice, ASM International, Materials Park,<br />

OH, 1984.<br />

QUESTIONS AND PROBLEMS<br />

Vacancies and Self-Interstitials<br />

4.1 Calculate the fraction of atom sites that are<br />

vacant for lead at its melting temperature of<br />

327C (600 K). Assume an energy for vacancy<br />

formation of 0.55 eV/atom.<br />

4.2 Calculate the number of vacancies per cubic<br />

meter in iron at 850C.The energy for vacancy<br />

formation is 1.08 eV/atom. Furthermore, the<br />

density and atomic weight for Fe are 7.65<br />

g/cm 3 (at 850ºC) and 55.85 g/mol, respectively.<br />

4.3 Calculate the activation energy for vacancy<br />

formation in aluminum, given that the equilibrium<br />

number of vacancies at 500C (773 K)<br />

is 7.57 10 23 m 3 .The atomic weight and density<br />

(at 500C) for aluminum are, respectively,<br />

26.98 g/mol and 2.62 g/cm 3 .<br />

Impurities in Solids<br />

4.4 Atomic radius, crystal structure, electronegativity,<br />

and the most common valence are<br />

tabulated in the following table for several elements;<br />

for those that are nonmetals, only<br />

atomic radii are indicated.<br />

Atomic<br />

Radius Crystal Electro-<br />

Element (nm) Structure negativity Valence<br />

Cu 0.1278 FCC 1.9 2<br />

C 0.071<br />

H 0.046<br />

O 0.060<br />

Ag 0.1445 FCC 1.9 1<br />

Al 0.1431 FCC 1.5 3<br />

Co 0.1253 HCP 1.8 2<br />

Cr 0.1249 BCC 1.6 3<br />

Fe 0.1241 BCC 1.8 2<br />

Ni 0.1246 FCC 1.8 2<br />

Pd 0.1376 FCC 2.2 2<br />

Pt 0.1387 FCC 2.2 2<br />

Zn 0.1332 HCP 1.6 2<br />

Which of these elements would you expect to<br />

form the following with copper:

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