The Effect of Film Thickness on Fatigue Fracture Properties in Rolled Copper Film.
The Effect of Film Thickness on Fatigue Fracture Properties in Rolled Copper Film.
复制标题
膜厚度对轧制铜膜疲劳断裂性能的影响。
DOI：
10.1299/kikaia.69.654
复制
发表时间：
2003
期刊：
影响因子：
--
通讯作者：
T. Torii
中科院分区：
文献类型：
--
作者：
K. Shimizu;T. Torii
采用一种新的疲劳试验方法，即在推拉循环载荷作用下，疲劳裂纹在覆盖在基板椭圆通孔上的薄膜中萌生和扩展，对100和30 μm厚的冷轧铜薄膜在不同应力幅下进行疲劳试验，应力比R=0.采用轧制方向与加载方向平行和垂直两种试样，研究了薄膜厚度和轧制方向对疲劳断裂性能的影响。结果表明，对于30 μm厚的薄膜，垂直于轧制方向的加载比平行于轧制方向的加载在应力幅较低的情况下产生裂纹，且疲劳裂纹向与轧制方向平行的方向扩展比向垂直的方向扩展快。由于轧制拉伸晶粒形状的不同，两种试样表面裂纹观察结果存在差异。薄膜厚度越薄，疲劳极限越低，疲劳裂纹扩展速率越高，而应力强度因子范围ΔKest（由实验测得的裂纹张开位移估算）相同。冷轧纯铜薄膜中厚度效应的原因可能是薄膜中的裂纹比厚膜中的裂纹更容易沿膜厚扩展。
Using a new fatigue testing method by which fatigue cracks can be initiated and propagated in a film adhered to cover an elliptical through-hole in a base plate subjected to push-pull cyclic loads, cold rolled copper films of 100 and 30 μm thickness were fatigued under various stress amplitudes with a stress ratio of R=0. The effects of the film thickness and the rolling direction on fatigue fracture properties were studied using two types of specimens that the rolling direction was parallel and perpendicular to the loading direction. As a result, for the case of films of 30 μm thickness, the crack initiation was caused at lower stress amplitude in the film with the loading direction perpendicular than parallel to the rolling direction, and the fatigue crack propagates faster toward the parallel direction to the rolling direction than toward the perpendicular direction. There was a difference between the two types of specimen in crack observation on the specimen surface owing to the difference in the shape of grains stretched by rolling. The thinner the film thickness was, the lower the fatigue limit was and the higher the fatigue crack propagation rate was against the same stress intensity factor range, ΔKest, evaluated from the crack opening displacement measured experimentally. The reason of the effects of thickness in the cold rolled pure copper film was probably that the crack propagates easier through the film thickness in the thin films than in the thick ones.