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研究了一种新型镍基合金在750℃下长期时效1500 h过程中的组织变化及其对750℃高温拉伸性能的影响。利用扫描电子显微镜对合金长期时效过程中的显微组织和高温拉伸断口进行了观察分析。结果表明:GH4586B合金在时效过程中晶界和晶内均有碳化物析出,晶界析出碳化物的形貌呈弥散的颗粒状,并随时效时间的延长有逐步转变为连续链状的趋势,同时合金内未见有害拓扑密堆(TCP)相析出;合金在750℃高温下拉伸,随着时效时间的延长合金的强度和塑性在500 h时表现为峰值,且随着时效时间的延长略有降低,这与晶界析出碳化物的形貌、分布、数量直接相关;通过750℃高温拉伸断口的形貌分析,合金断裂均具有塑性断裂特征。
The microstructure changes of a new nickel-based alloy during 750 h aging at 750 ℃ and its effect on the tensile properties at 750 ℃ were investigated. The microstructure and high temperature tensile fracture of the alloy during long-term aging were observed and analyzed by scanning electron microscope. The results show that the carbide precipitates in the grain boundary and in the grain during the aging process, and the morphology of precipitated carbide in the grain boundary is in the form of dispersed particles. With the aging time increasing, the carbide gradually changes into a continuous chain. At the same time, there was no precipitated TCP in the alloy. The alloy was stretched at a high temperature of 750 ℃. The strength and ductility of the alloy peaked at 500 h with the aging time. With the extension of the aging time It is directly related to the morphology, distribution and quantity of precipitated carbides in the grain boundaries. The morphology of the fracture at high temperature of 750 ℃ shows that all the fractures have the characteristics of plastic fracture.