Crystal Rotation with Fatigue Crack Propagation in Copper Films

Abstract

The fatigue crack initiation and propagation behaviors were examined for pure copper films of 100 μm thickness. The cold rolled films were annealed and adhered to cover a circular through hole in a base plate. The base plate was subjected to constant cyclic stress with a stress ratio of R = 0. In order to discuss correlation between fatigue crack propagation and change of crystal orientation, crystal orientation on the surface of the copper film was measured before and after fatigue testing. The crystallographic information of these films was analyzed using the Electron Back-scatter Diffraction (EBSD) system and the quantitative evaluation method for the crystal rotation angle and the rotation axis, the rotation direction with fatigue was developed. As a result, the crystal rotation angle near the fatigue crack is larger than that apart from the crack but that is quantitatively small around the crack propagated on the annealing twin boundary.