Slip behavior and local stress near grain boundary in high-cycle fatigue of copper polycrystal

Abstract

Recent development of OIM (Orientation Imaging Microscope) makes the measurement of crystal orientation easy and advanced computer technology allow us to conduct a detailed stress analysis of component with microstructure. In this study, a high cycle fatigue test was carried out for a copper polycrystal, where the shape and orientation of each crystal is measured by the OIM. 13 PSBs are found along the grain boundaries, and the location and slip system are different from those expected by the Schmid factor. FEM analysis is conducted for the copper polycrystal with the same orientation and shape. It reveals that the increase of resolved shear stress, τrss, of specific slip system due to the constraint of deformation between grains causes the unique slip behavior near the grain boundary.