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

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

2nd Revised Pages

458 • Chapter 11 / Phase Transformations

the higher melting temperature and then cite

reason(s) for your choice; and (3) if it is not

possible to decide, then state why.

(a)Branched polyethylene having a number-

average molecular weight of 850,000

g/mol; linear polyethylene having a

number-average molecular weight of

850,000 g/mol

(b)Polytetrafluoroethylene having a den-

sity of 2.14 g/cm^3 and a weight-average

molecular weight of 600,000 g/mol; PTFE

having a density of 2.20 g/cm^3 and

a weight-average molecular weight of

600,000 g/mol

(c)Linear and syndiotactic poly(vinyl chlo-

ride) having a number-average molecular

weight of 500,000 g/mol; linear polyethy-

lene having a number-average molecular

weight of 225,000 g/mol

(d)Linear and syndiotactic polypropy-

lene having a weight-average molecu-

lar weight of 500,000 g/mol; linear and

atactic polypropylene having a weight-

average molecular weight of 750,000

g/mol

DESIGN PROBLEMS

Continuous Cooling Transformation Diagrams

Mechanical Behavior of Iron–Carbon Alloys

11.D1Is it possible to produce an iron–carbon

alloy of eutectoid composition that has a

minimum hardness of 200 HB and a mini-

mum ductility of 25% RA? If so, describe the

continuous cooling heat treatment to which

the alloy would be subjected to achieve these

properties. If it is not possible, explain why.

11.D2It is desired to produce an iron–carbon al-

loy that has a minimum hardness of 200 HB

and a minimum ductility of 35% RA. Is such

Temperature (

°C)

1000

800

600

400

0

(Cu)

1234

Composition (wt% Be)

Composition (at% Be)

5101520

Liquid

866 °C

~620°C

+ 1

+ 2

+ L



0

Figure 11.51 The copper-rich side of the copper–

beryllium phase diagram. [Adapted fromBinary Alloy

Phase Diagrams, 2nd edition, Vol. 2, T. B. Massalski

(Editor-in-Chief), 1990. Reprinted by permission of

ASM International, Materials Park, OH.]

an alloy possible? If so, what will be its com-

position and microstructure (coarse and fine

pearlites and spheroidite are alternatives)?

If this is not possible, explain why.

Tempered Martensite

11.D3An alloy steel (4340) is to be used in an appli-

cation requiring a minimum tensile strength

of 1515 MPa (220,000 psi) and a minimum

ductility of 40% RA. Oil quenching followed

by tempering is to be used. Briefly describe

the tempering heat treatment.