热处理对粉末冶金Inconel 718高温合金组织及性能的影响

Effect of Heat Treatment on Microstructure and Mechanical Properties of P/M Inconel 718 Superalloy

以超高转速等离子旋转电极法(SS-PREP法)制备的高球形度Inconel 718高温合金粉末为原料,采用热等静压(HIP)工艺制备了Inconel 718粉末高温合金,重点研究了热处理制度对合金组织和力学性能的影响。实验结果表明:采用SS-PREP法制得的Inconel 718高温合金粉末粒度分布均匀,球形度良好,具有优异的HIP工艺性能;随着固溶温度的提高,合金晶界逐渐变浅,说明晶界析出相数量逐渐减少。时效热处理后,沿晶界析出大量针状δ相,同时还有少量MC碳化物相。在1210℃、120MPa条件下保温保压4h的HIP工艺下,经1020℃固溶热处理后,合金室温抗拉强度可达1404MPa;经980℃固溶处理后,合金在650℃的高温抗拉强度为1153MPa,固溶处理温度为980℃的合金综合性能较好。

Powder metallurgy(P/M) Inconel 718 superalloy was prepared through hot isostatic pressing(HIP) route from super-speed plasma rotating electrode process(SS-PREP) powder. Effect of heat treatment on the microstructure and mechanical properties of superalloy was studied. The results indicate that Inconel 718 superalloy powder prepared by SS-PREP method has good sphericity and excellent HIP process performance, and its particle size distribution is uniform;with the increase of solution temperature, the grain boundary of the alloy gradually becomes shallower, which indicates that the amount of precipitated phase at grain boundary gradually decreases. After aging treatment, a large amount of needle-like δ phases precipitate along grain boundary, at the same time, a small amount of MC carbides precipitate along the grain boundary as well. The RT tensile strength of the alloy after solution heat treatment at 1020 °C can reach 1404 MPa, and the HT tensile strength of the alloy at 650 °C is 1153 MPa after solution treatment at 980 °C, and the comprehensive properties of the alloy with solution treatment at 980 °C are better.