Basic Research on Slip-initiation Phenomenon by Fatigue and Its Application to Stress Measurement

Abstract

In order to utilize a slip-initiation phenomenon in metal by fatigue for stress measurement, the phenomenon in pure iron is examined. It is found that at high temperature the slip-initiation phenomenon is not affected by interrupting the test, unlike the growth of crystal grains in the electro-plating method of stress analysis. By applying chromium evaporation on the surface of a notched specimen to protect oxidation of the material and using the present technique, the concentrated stress at the bottom of the notch can be measured accurately in the high temperature range below 300°C.