QUANTITATIVE EVALUATION OF CRYSTAL ROTATION BEHAVIOR AROUND THE FATIGUE CRACK IN COPPER FILMS

摘要

Using a fatigue testing method by which fatigue cracks can be initiated and propagated in a film adhered to cover a circular through-hole in a base plate subjected to pull-pull cyclic loads, annealed rolled pure copper films of 100μm thickness were fatigued. In order to discuss about the correlation between fatigue crack propagation and the change of crystal orientation, crystal orientation on the surface of the film materials was measured before and after fatigue testing. The crystallographic information of these films was analyzed using the EBSD (Electron Back-scatter Diffraction) system and the quantitative evaluation method for the crystal rotation angle, the rotation axis and the rotation direction with fatigue testing was developed based on the analysis of crystal orientation matrix. As a result, the crystal rotation angle near the fatigue crack is larger than that apart from the crack and the crystal rotation was quantitatively larger around the transgranular crack than the inter-granular crack propagated along the annealing twin boundary.