Effect of Hole Cold Expansion on Fatigue Property of FGH95 Superalloy Under Room and High Temperature
YU Yang1, LUO Xuekun1, LIU Yongjun2, XU Xin2, SUN Ruijia2, WANG Xin1, ZHONG Bintao2, TANG Zhihui1
1. Aviation Key Laboratory of Advanced Corrosion and Protection on Aviation Material, AECC Beijing Institute of Aeronautical Materials, Beijing 100095, China;
2. AECC Hunan Aviation Powerplant Research Institute, Zhuzhou 412002, China
Hole is widely considered as a kind of geometrical–discontinuous structure with high stress or strain concentration.The effect of direct hole cold expansion (HCE) using the mandrel on the fatigue behaviour of centre holes of FGH95 superalloy was investigated. The fatigue fracture and the main parameters of surface integrity of hole wall were characterized by scanning electron microscopy (SEM), roughmeter, X–ray diffraction (XRD) instrument and microhardness tester. The mechanism of the HCE on the fatigue life was also investigated. The results show that the median fatigue life of the HCE specimens increased by above 0.9 times and 10.3 times under room temperature/650MPa and 527℃/575MPa conditions compared to the specimen without HCE, respectively. It is found that the roughnesss of hole wall decreased sharply, while the deep surface strengthened layer with high hardness and residual compressive stress were formed around the hole after HCE. These changes are of great benefit to the enhancement of the fatigue life under room and high temperature. In addition, the exit of grain boundary and the difference of crystallographic orientation of neighbor grains have an evident effect on the fatigue crack growth path.
引用本文:
于洋,罗学昆,刘勇军,许欣,孙瑞嘉,王欣,钟滨涛,汤智慧. 孔挤压强化对FGH95合金室温及高温疲劳性能的影响[J]. 航空制造技术, 2019, 62(18): 76-82.
YU Yang, LUO Xuekun, LIU Yongjun, XU Xin, SUN Ruijia, WANG Xin, ZHONG Bintao, TANG Zhihui. Effect of Hole Cold Expansion on Fatigue Property of FGH95 Superalloy Under Room and High Temperature. Aeronautical Manufacturing Technology, 2019, 62(18): 76-82.