銅膜材の疲労破壊特性に及ぼす圧延方向の影響(<小特集>材料のミクロ・メゾ評価)

概要

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In recent years, films have been widely used as the small-sized and light-weight materials for electronic parts. Therefore, it is important to know mechanical properties of the film. For reliability of these parts, it is particularly necessary to evaluate fatigue fracture properties of the film. In this study, the effect that rolling direction of the copper film influenced slip initiation, microcrack initiation, and fatigue life was studied. The two types of specimen that rolling direction was parallel and perpendicular to loading direction were prepared in film fatigue testing. moreover, stress intensity factors were calculated using BEM analysis. As a result, a slip and a crack initiate at less number of cycles and lower stress amplitude in the film loaded to the perpendicular direction than in that loaded to the parallel direction. Conversely, a crack in the film loaded to the perpendicular direction propagates slower than that in the film loaded to the parallel direction. There was a difference between the two types of specimen in crack observation on the specimen surface. The reason was probably that deformation restraint due to grain boundary was different in accordance with the aspect ratio of the grain stretched by rolling.
一般社団法人日本機械学会の論文
1999-03-25