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

GTBL042-11 GTBL042-Callister-v3 October 4, 2007 11:59

2nd Revised Pages

Design Problems • 459

Heat Treatments (Precipitation Hardening)

11.D4Copper-rich copper–beryllium alloys are

precipitation hardenable. After consulting

the portion of the phase diagram (Figure

11.51), do the following:

(a)Specify the range of compositions over

which these alloys may be precipitation

hardened.

(b)Briefly describe the heat-treatment pro-

cedures (in terms of temperatures) that

would be used to precipitation harden

an alloy having a composition of your

choosing, yet lying within the range

given for part (a).

Mechanism of Hardening

11.D5Is it possible to produce a precipitation hard-

ened 2014 aluminum alloy having a mini-

mum yield strength of 380 MPa (55,000 psi)

and a ductility of at least 15% EL? If so,

specify the precipitation heat treatment. If

it is not possible then explain why.