Page 178 - Mechanical Behavior of Materials

Problems and Questions 179

Table P4.6
σ,MPa ε, % σ,MPa ε, %
0 0 309 2.00
50 0.069 315 3.51
100 0.138 319 5.02
151 0.210 322 6.51
199 0.280 323 7.44
242 0.343 320 8.48
268 0.384 311 9.52
290 0.438 293 10.90
298 0.493 267 12.51
302 0.651 246 13.63
305 0.992 223 14.59
(Final point is fracture.)

ε, Strain (Curve 2), %
0 2 4 6 8 10 12 14 16
350

300
Curve 2
250
σ, Stress, MPa 200 Initial Data, Curve 1 Fracture

150
100
6061-T6 Aluminum
50
0
0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 1.6
ε, Strain (Curve 1), %

Figure P4.6

4.7 Engineering stress–strain data from a tension test on gray cast iron are given in Table P4.7.
The diameter before testing was 10 mm, and after fracture it was 9.5 mm.
(a) Determine the following: tangent modulus, 0.2% offset yield strength, ultimate tensile
strength, percent elongation, and percent reduction in area.
(b) How do these properties differ from the corresponding values for ductile cast iron in
Table 4.2? Referring to Section 3.3, explain why these two cast irons have contrasting
tensile behavior.