抄録
The true tensile stress and the natural strain are found to be correlated with the excess dislocation density obtained from X-ray microbeam observation and with micro Vickers hardness value, as has been reported in the preceding paper. In the present study, the excess dislocation density of fatigued specimens, was measured and used to estimate the flow stress and the strain at specific localized region in these specimens, such as crack tips. The stress concentration factor at the crack tip was evaluated successfully.
The method to estimate the flow stress and the strain from the excess dislocation density or from micro Vickers hardness value was also applied to the estimation of these quantities in various kinds of specimens, including the tensile specimens fractured at low temperature, the Charpy impact specimens fractured at several temperature levels below room temperature, the creep specimens deformed at 450°C or ruptured at 500°C and the cold-rolled specimens. And the applicability of this method was discussed in each case.
