热等静压温度对K447A高温合金显微组织及性能的影响

研究了热等静压温度对K447A合金显微组织及性能的影响。测试了合金的持久性能和室温拉伸性能。利用金相显微镜(OM)和扫描电镜(SUM)观察了合金显微组织。结果表明,1185～1210℃/180MPa/4h(+1185℃/2h,AC+1100℃/4h,AC+870℃/20h,AC)下,随热等静压温度的提高,合金中显微疏松逐步闭合,碳化物逐步细化和球化;γ-γ’共晶相尺寸和数量逐步减小,共晶特征趋于不明显;晶界呈不连续颗粒状;存在大、小两种尺寸的γ’相。经1185～1210℃HIP处理的合金980℃/200MPa持久性能大幅提高;经1195℃HIP的合金760℃/724MPa持久性能达到最高。经1210℃HIP处理的合金980℃/200MPa持久性能达到最高。180MPa/4h条件下,K447A合金合适的热等静压温度为1185～1210℃。

Effects of HIP Temperature on Microstructure and Mechanical Properties of K447A Superalloy

The effects of HIP temperature on microstructure and mechanical properties of superalloy were studied.The results show that with the increasing of HIP temperature,the microstructure and mechanical properties are changed obviously,i.e.the microporosity of the alloy is eliminated,the change of the size and shape of the primary MC carbide phase shows the fact of the carbide refinement and spheroidization,the amount of γ-γ′eutectic phase decreases and the amount of fine regular γ′phase increases.The grain boundary of the alloy is not good due to the increase of the size of γ′phase after the treatment of the 1230℃HIP.The stress rupture life of 980℃/200MPa is improved greatly after the treatment of 1185℃HIP,1195℃HIP,1210℃HIP.However,the stress rupture life of 760℃/724MPa is improved after the treatment of 1210℃HIP.Hence,the best HIP temperature is 1185-1210℃ under the condition of 180MPa/4h.