热处理对激光熔化沉积成形GH3536合金组织演变的影响

Effect of Heat Treatment on Microstructure Evolution of GH3536 Alloy Formed by Laser Melting Deposition

利用激光熔化沉积(LMD)成形技术制备GH3536镍基高温合金,利用X射线衍射(XRD)、扫描电子显微镜(SEM)、电子探针(EPMA)等方法研究双级时效处理、固溶处理+双级时效处理对GH3536合金组织演变的影响规律、表征相组成和组织情况。结果表明:GH3536合金粉末相组成为γ固溶体;沉积态GH3536合金相组成为γ固溶体,晶界有粒状相析出;双级时效处理后,晶界析出针状相和片层状相;LMD沉积态试样经固溶处理后,合金元素扩散加强,熔池边界逐渐消失;提高固溶处理温度,固溶处理+双级时效处理后,除晶界上的析出相外,晶粒内部也出现弥散析出相。EPMA结果表明,这些相富含C、Cr、Mo,主要相组成是Laves相和碳化物。

The nickel-based high-temperature GH3536 alloys were prepared by laser melting deposition(LMD)technique, and X-ray diffraction(XRD), scanning electron microscopy(SEM), and electron microprobe(EPMA) were used to study the effects of double-stage aging treatment, solid solution treatment+double-stage aging treatment on the structure evolution of the GH3536 alloy. The results show that the phase composition of the GH3536 alloy powder was γ solid solution;the phase composition of the GH3536 alloy in the deposited state was γ solid solution with grainy phase precipitated at the grain boundaries;after the double-stage aging treatment, the pin-like phase and lamellar phase precipitated at the grain boundaries;after the solid solution treatment of the LMD deposited state specimen, the diffusion of alloy elements was enhanced and the melt pool boundary gradually disappeared;after increasing the solid solution treatment temperature, the solid solution treatment+double-stage aging treatment, some dispersed precipitates also appeared in the grain except for the precipitated phase at the grain boundaries. The EPMA results show that these phases were rich in C, Cr and Mo, and the main phase composition was Laves phase and carbide.