长期热暴露对新型电站用Ni-Cr-Co型镍基合金组织及力学性能的影响

The effect of long term thermal exposure on microstructure and mechanical properties for a newly developed Ni-Cr-Co base Power Plants used Superalloy

摘要: 对一种新型电站用Ni-Cr-Co型镍基合金在850℃进行5000h热暴露试验，采用扫描电镜（SEM）和拉伸机等技术对原始组织及不同热暴露时间试样进行了测试与表征，研究了热暴露时间对组织及力学性能的影响规律。结果表明：经过标准热处理的组织主要由MC、晶界M23C6及晶内析出相ϒ′组成，随着时效时间延长，ϒ′相尺寸逐渐增加，M23C6略有粗化；合金强度呈现先上升后下降的规律，但波动较小。长期热暴露后的合金组织及性能变化表明新型Ni-Cr-Co型镍基合金在850℃/5000h的情况下合金组织稳定性较好。

Abstract: Thermal exposure test of a newly developed Ni-Cr-Co base superalloy was carried out at 850℃ for 5000h. The microstructures of the samples before and after thermal exposure were tested and characterized by SEM and tensile testing machine. The effects of exposure time on the mechanical property and microstructure were also studied. The results show that the microstructure was consisted of MC, M23C6 and ϒ′ precipitation. With the exposure time, the size of ϒ increases gradually and M23C6 slightly coarsens. The ultimate strength increases firstly and then decreases, but the fluctuation is slight. The change of microstructure and mechanical property indicate that a newly developed Ni-Cr-Co base superalloy has good microstructure stability at 850℃/5000h.