Abstract
The copper electroplating stress measurement method utilizes the grain growth in the copper on a machine element that has been subjected to repeated loads. Since the grain growth is also caused by thermal energy, an effect of ambient temperature on grown grain density and grain orientation was investigated. Cyclic torsion tests were carried out at temperatures from 293K to 353K. The relationship among grown grain density, maximum shearing stress, number of cycles and ambient temperature was formulated to measure the maximum shearing stress occurring on the machine element. Moreover, the cyclic bending-torsion tests were also performed and the orientation of grown grain was analyzed by EBSD. The slip direction of grown grain corresponded closely with the direction of shearing stress in spite of ambient temperatures. This means that principal stresses can be measured using the pole figure and the inverse pole figure map of grown grain at temperatures up to 353K.
