一种含Re单晶高温合金的拉伸断裂行为

研究了Re对单晶高温合金拉伸、持久性能的影响及含Re单晶的拉伸断裂特征。拉伸性能试样采用001]取向单晶制备，应力轴方向平行于单晶001]取向，采用扫描电镜观察断口形貌。实验结果表明：Re的加入降低了单晶短时拉伸延伸率，但能提高单晶的高温持久断裂延伸率；含Re单晶室温拉伸表现为滑移开裂特征；高温拉伸断裂失效机制为变形不均匀的蠕变断裂；高温持久断口表现为典型的塑性断裂特征，变形均匀。

Tensile and Fracture Behaviour of a Single Crystal Superalloy Containing Re

The effects of Re on the tensile and stress-rupture properties and fracture behaviour of a single crystal superalloy containing Re were studied. Tensile specimens were prepared from this single-crystal with 001 ] orientation. The fractograph was examined by means of scanning electron microscope. The test specimens had the 001 ] growth direction parallel to the loading axis in tension. The results of the present investigation indicate that the tensile elongation of single crystal superalloy significantly decreased, but the stress-rupture elongation at high temperature increased with Re addition. The fractograph of fracture surface for the tensile specimen at room temperature showed a slide fracturing mode. The fractograph at elevated temperature showed a creep rupture mode with uneven deformation. The fractograph of fracture surface for the stress rupture specimen showed a typically ductile fracturing mode and the deformation was even.