粉末高温合金FGH96原始颗粒边界及高温原位高周疲劳研究

Prior Particle Boundary of PM FGH96 Superalloy and Its In-situ High-cycle Fatigue at Elevated Temperature

利用扫描电镜原位观察的方法研究了粉末高温合金FGH96中不同级别的原始颗粒边界(PPB)在550℃下对合金高周疲劳力学行为的影响。结果表明:采用等离子旋转电极(PREP)制粉+热等静压(HIP)工艺制备的FGH96合金中PPB主要由大尺寸γ'相和碳化物组成;不同级别的PPB对高周疲劳裂纹萌生和扩展均无显著影响,裂纹萌生于晶粒内部,裂纹扩展受晶界与应力轴角度影响,穿晶或沿晶扩展;在裂纹快速扩展区和瞬断区,PPB级别严重的FGH96合金断口呈现穿晶和沿PPB断裂的形貌。

The influence of different grades of prior particle boundary （ PPB） in PM FGH96 superalloy during high-cycle fatigue test at 550 ℃was investigated by the insitu fatigue test in SEM. The results show that the PPB in P/M FGH96 superalloys by plasma rotating electrode process （PREP） ＋ hot isostatic press （HIP） is constituted of large size and carbide. There are no significant effect on the initiation and propagation of high cycle fatigue crack in different grades of PPB. Crack initiation is initiated in the grain interior, and the propagation is transgranular or intergranular, which is influenced by the angle between the grain boundary and the stress axis. In the fast crack growth zone and the transient zone, the fracture characteristics of serious grade PPB FGH96 superalloy are transgranu-lar and along PPB globular surfaces.