K4202镍基高温合金激光选区熔化成形室温拉伸性能研究

Mechanical properties of selective laser melted and shaped K4202 nickel-based superalloy at room temperature

为了将激光选区熔化(SLM)这项技术推广到液体火箭发动机高温合金复杂结构件的成形,满足其使用要求,对SLM成形K4202高温合金力学性能及其强化机理进行研究。沉积态室温下拉伸试验力学性能指标表现出了很强的各向异性,但均接近或超过GH4202锻件标准值,通过光学显微镜(OM)、扫描电镜(SEM)、X射线衍射(XRD)、透射电镜(TEM)等理化分析手段揭示了其强化机理主要为细晶强化、应变硬化、沉淀硬化和过饱和的固溶强化。同时研究了固溶、固溶时效、直接时效三种热处理制度对K4202力学性能的影响,结果表明直接时效后的综合力学性能最佳。

In order to promote selective laser melting （SLM） to shaping of superalloy complicated structural components of liquid rocket, and meet its requirement, the mechanical property and strength mechanism of K4202 superalloy formed by SLM are analysed. The tensile tests were executed in the deposited state at room temperature. The mechanical performance index got from the tests shows a very strong anisotropy, even is close to or exceeds the standard value of GH4202 alloy forgings. Physical and chemical analysis means of optical micrographs （OM）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD） etc. revealed its main strength mechanism, which is fine-grain strengthening, strain hardening and supersaturation solution strengthening. Three heat treatments of solution, solution aging and direct aging were studied in order to evaluate the influence on the mechanical properties of K4202 superalloy. The research result shows that the mechanical properties of the superalloy after direct aging heat treatment are the best.