Page 377 - Materials Science and Engineering An Introduction

Questions and Problems • 349

Important Terms and Concepts

austenite hypereutectoid alloy phase diagram
cementite hypoeutectoid alloy phase equilibrium
component intermediate solid solution primary phase
congruent transformation intermetallic compound proeutectoid cementite
equilibrium isomorphous proeutectoid ferrite
eutectic phase lever rule solidus line
eutectic reaction liquidus line solubility limit
eutectic structure metastable solvus line
eutectoid reaction microconstituent system
ferrite pearlite terminal solid solution
free energy peritectic reaction tie line
Gibbs phase rule phase
REFERENCES

ASM Handbook, Vol. 3, Alloy Phase Diagrams, ASM ASM International, Materials Park, OH, 1990. Three vol-
International, Materials Park, OH, 1992. umes. Also on CD-ROM with updates.
ASM Handbook, Vol. 9, Metallography and Microstructures, Okamoto, H., Desk Handbook: Phase Diagrams for Binary
ASM International, Materials Park, OH, 2004. Alloys, 2nd edition, ASM International, Materials Park,
Campbell, F. C., Phase Diagrams: Understanding the Basics, OH, 2010.
ASM International, Materials Park, OH, 2012. Villars, P., A. Prince, and H. Okamoto (Editors), Handbook
Massalski, T. B., H. Okamoto, P. R. Subramanian, and L. of Ternary Alloy Phase Diagrams, ASM International,
Kacprzak (Editors), Binary Phase Diagrams, 2nd edition, Materials Park, OH, 1995. Ten volumes. Also on CD-ROM.

QUESTIONS AND PROBLEMS
Problem available (at instructor’s discretion) in WileyPLUS

Solubility Limit One-Component (or Unary) Phase Diagrams
9.1 Consider the sugar–water phase diagram of 9.5 Consider a specimen of ice that is at 15 C and 10
Figure 9.1. atm pressure. Using Figure 9.2, the pressure–tem-
(a) How much sugar will dissolve in 1000 g of perature phase diagram for H 2 O, determine the
water at 80 C (176 F)? pressure to which the specimen must be raised or
lowered to cause it (a) to melt and (b) to sublime.
(b) If the saturated liquid solution in part (a) is 9.6 At a pressure of 0.1 atm, determine (a) the melt-
cooled to 20 C (68 F), some of the sugar precipi- the boiling tem-
tates as a solid. What will be the composition of the ing temperature for ice and (b)
perature for water.
saturated liquid solution (in wt% sugar) at 20 C?
Binary Isomorphous Systems
(c) How much of the solid sugar will come out of
solution upon cooling to 20 C? 9.7 Given here are the solidus and liquidus tempera-
tures for the copper–gold system. Construct the
9.2 At 100 C, what is the maximum solubility of the phase diagram for this system and label each region.
following:
(a) Pb in Sn Composition Solidus Liquidus
(wt% Au) Temperature ( C) Temperature ( C)
(b) Sn in Pb
0 1085 1085
Microstructure 20 1019 1042
9.3 Cite three variables that determine the micro- 40 972 996
structure of an alloy. 60 934 946
80 911 911
Phase Equilibria 90 928 942
9.4 What thermodynamic condition must be met for a 95 974 984
state of equilibrium to exist? 100 1064 1064