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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 extend the technique of laser selective melting (SLM) to the forming of complex structures of liquid rocket engine superalloy and meet the requirements of its application, the mechanical properties of SLM forming K4202 superalloy and its strengthening mechanism were studied. The mechanical properties of the as-deposited tensile specimens at room temperature showed strong anisotropy, but all approached or exceeded the standard values of GH4202 forgings. The mechanical properties of the as-deposited specimens were characterized by OM, SEM, XRD, Transmission electron microscopy (TEM) and other physical and chemical analysis means revealed that the strengthening mechanism is mainly fine-grain strengthening, strain hardening, precipitation hardening and supersaturated solid solution strengthening. The effects of solution heat treatment, solution treatment and aging treatment on the mechanical properties of K4202 were also studied. The results show that the composite has the best mechanical properties after direct aging.