Fundamentals of Materials Science and Engineering: An Integrated Approach, 3e

GTBL042-10 GTBL042-Callister-v2 August 13, 2007 18:16

Questions and Problems • 399

whereErepresents a specific property (mod-

ulus of elasticity, hardness, etc.), andVis the

volume fraction. The subscriptsαandβde-

note the existing phases or microconstituents.

Employ this relationship to determine the ap-

proximate Brinell hardness of a 99.75 wt%

Fe–0.25 wt% C alloy. Assume Brinell hard-

nesses of 80 and 280 for ferrite and pearlite,

respectively, and that volume fractions may

be approximated by mass fractions.

The Influence of Other Alloying Elements

10.37A steel alloy is known to contain 93.65 wt%

Fe, 6.0 wt% Mn, and 0.35 wt% C.

(a)What is the approximate eutectoid tem-

perature of this alloy?

(b)What is the proeutectoid phase when this

alloy is cooled to a temperature just be-

low the eutectoid?

(c)Compute the relative amounts of the

proeutectoid phase and pearlite. Assume

that there are no alterations in the posi-

tions of other phase boundaries with the

addition of Mn.