镍基单晶超合金的剪切强度研究

Shear Strength of a Nickel-Base Single Crystal Superalloy

通过设计滑移系直接受分切应力的剪切试样形式 ,对镍基单晶超合金在 70 0℃、850℃和 950℃时的瞬时剪切强度和剪切蠕变性能进行了研究。试验结果表明 ,本研究试样形式可以直接测量单滑移系的滑移规律 ,未发现晶体取向相关性。通过转换公式 ,瞬时剪切强度与圆棒试验结果相吻合。应用扫描电镜 (SEM)对试样断口分析表明 ,断口由平整的小刻面组成 ,从而进一步验证本试验的有效性 ,同时发现 ,由夹杂形成的空洞和平行受载方向的裂纹对瞬时和蠕变强度起着重要影响。

A special shear specimen has been developed for studying the shear strength of a nickel base single crystal superalloy and were used for studying the plastic and creep behavior at 700℃, 850℃ and 950℃. The shearing plane corresponds to the plane of slip systems, while the shearing direction corresponds to the slip direction of slip systems. A set of macro and micro experiments indicated that the specimen was suitable for measuring the slip rule of single slip systems without crystallographic dependence. The results obtained agreed with those obtained by using tensile bars. SEM analysis of the fractured surface reveals slip planes. It was noted that voids formed by inclusions and cracks have significant influence on the rupture strength.