Abstract
Using a fatigue testing method by which fatigue cracks can be initiated and propagate in a film adhered to cover an elliptical through-hole in a base plate subjected to push-pull cyclic loads, annealed rolled pure copper films of 100μm and 30μm thickness were fatigued under constant stress amplitudes with a stress ratio of R = 0. The effects of microstructures such as crystal orientation due to rolling on fatigue crack propagation behavior were studied using two types of specimens in which the rolling direction was parallel and perpendicular to the loading direction. The crystallographic characteristic of rolling textures in the annealed film was analyzed using "electron back-scatter diffraction (EBSD)" system. As a result, the fatigue crack propagated slower toward the perpendicular direction to the rolling direction than toward the parallel direction in the film with the thickness of 30μm. This is probable that the number of slip systems in the film loaded parallel to the rolling direction was found to be less than in the film loaded perpendicular to the rolling direction from a result of the slip analysis of the rolling texture in copper film materials. The effects of the anisotropy of the crystal orientation seemed to be greater in the thin film with a weak interaction between grains through the thickness than in the thick one.
