PPT Slide
The stress-strain curve and the flow and fracture properties derived from the tension test ate strongly
dependent on the temperature at which the test was conducted. In general strength decreases and ductility
increases as the test temperature increased. However, structural changes such as precipitation, strain aging,
or recrystallization may occur in certain temperature ranges to alter this general behavior. Thermally
activated processes assist deformation and reduce strength at elevated temperatures. At high temperatures
and/or long exposure, structural changes occur resulting in time-dependent deformation or creep. These
topics are discussed in greater detail in Chapter 13.
Figure 2-1. Yield strength changes as a function of (a) temperature and (b) strain
Figure 2-2. Changes in engineering stress-strain curve of mild steel