GH169蠕变/疲劳交互作用下裂纹扩展研究

本文采用翻转电位法,研究了航空发动机的涡轮盘材料GH169在650℃时不同保持时间的蠕变疲劳交互作用下的裂纹扩展行为,进行了两种不同预测模型的比较,并用扫描电镜对断口作了微观分析。实验结果表明,利用Paris公式拟合初始裂纹扩展阶段实验数据时相关性差,但双曲正弦寿命预测模型具有良好的相关性及预测性,且这种模典更为方便实用。在实验中还发现逐次从小载荷循环增至大载荷循环的裂纹扩展速率比一次加载明显减慢。

A STUDY ON GH169 CRACK PROPAGATION UNDER CREEP-FATIGUE INTERACTION

As a new technique of crack detection at high temperatures, Reversing DC Electric Potential Method is used to study the crack propagation behaviours of aeroengine turbine disk material GH169 under creep-fatigue interaction at 650 C and at different hold-times. The fracture surfaces has examined with a scanning electron microscope. The experimental results indicate that the life prediction model by hyperbolic sine function is superior to the life prediction model by Paris formulation in correlativity with experimental data and predictability at the crack initiation propagation. Moreover, the former model is more convenient in application. It has been found that the crack propagation ratio obtained in the case of gradually increasing loading is smaller than that resulted from one-time loading.