Callister - An introduction - 8th edition

192 • Chapter 6 / Mechanical Properties of Metals
circumstances, what must be the radius of the
specimen? Consider this brass alloy to have the
stress–strain behavior shown in Figure 6.12.
6.27 A load of 85,000 N (19,100 lb f ) is applied to
a cylindrical specimen of a steel alloy (displaying
the stress–strain behavior shown in Figure
6.21) that has a cross-sectional diameter
of 15 mm (0.59 in.).
(a) Will the specimen experience elastic
and/or plastic deformation? Why?
(b) If the original specimen length is 250 mm
(10 in.), how much will it increase in length
when this load is applied?
6.28 A bar of a steel alloy that exhibits the
stress–strain behavior shown in Figure 6.21 is
subjected to a tensile load; the specimen is 300
mm (12 in.) long and has a square cross section
4.5 mm (0.175 in.) on a side.
(a) Compute the magnitude of the load necessary
to produce an elongation of 0.45 mm
(0.018 in.).
(b) What will be the deformation after the
load has been released?
6.29 A cylindrical specimen of aluminum having a
diameter of 0.505 in. (12.8 mm) and a gauge
length of 2.000 in. (50.800 mm) is pulled in
tension. Use the load–elongation characteristics
shown in the following table to complete
parts (a) through (f).
Load
Length
N lb f mm in.
0 0 50.800 2.000
7,330 1,650 50.851 2.002
15,100 3,400 50.902 2.004
23,100 5,200 50.952 2.006
30,400 6,850 51.003 2.008
34,400 7,750 51.054 2.010
38,400 8,650 51.308 2.020
41,300 9,300 51.816 2.040
44,800 10,100 52.832 2.080
46,200 10,400 53.848 2.120
47,300 10,650 54.864 2.160
47,500 10,700 55.880 2.200
46,100 10,400 56.896 2.240
44,800 10,100 57.658 2.270
42,600 9,600 58.420 2.300
36,400 8,200 59.182 2.330
Fracture
(a) Plot the data as engineering stress versus
engineering strain.
(b) Compute the modulus of elasticity.
(c) Determine the yield strength at a strain
offset of 0.002.
(d) Determine the tensile strength of this alloy.
(e) What is the approximate ductility, in percent
elongation?
(f) Compute the modulus of resilience.
6.30 A specimen of ductile cast iron having a rectangular
cross section of dimensions 4.8 mm
3 5
15.9 mm ( 16 in. 8 in.) is deformed in tension.
Using the load–elongation data shown in the
following table, complete parts (a) through (f).
Load
Length
N lb f mm in.
0 0 75.000 2.953
4,740 1,065 75.025 2.954
9,140 2,055 75.050 2.955
12,920 2,900 75.075 2.956
16,540 3,720 75.113 2.957
18,300 4,110 75.150 2.959
20,170 4,530 75.225 2.962
22,900 5,145 75.375 2.968
25,070 5,635 75.525 2.973
26,800 6,025 75.750 2.982
28,640 6,440 76.500 3.012
30,240 6,800 78.000 3.071
31,100 7,000 79.500 3.130
31,280 7,030 81.000 3.189
30,820 6,930 82.500 3.248
29,180 6,560 84.000 3.307
27,190 6,110 85.500 3.366
24,140 5,430 87.000 3.425
18,970 4,265 88.725 3.493
Fracture
(a) Plot the data as engineering stress versus
engineering strain.
(b) Compute the modulus of elasticity.
(c) Determine the yield strength at a strain
offset of 0.002.
(d) Determine the tensile strength of this alloy.
(e) Compute the modulus of resilience.
(f) What is the ductility, in percent elongation?
6.31 For the titanium alloy, whose stress-strain behavior
may be observed in the “Tensile Tests”