热等静压对K4169高温合金组织与性能的影响

摘要

对K4169高温合金铸件后处理工艺进行研究，通过拉伸试验、持久和疲劳测试，并结合光学显微镜、扫描电镜和透射电镜分析，研究热等静压处理对合金组织和综合力学性能的影响规律。结果表明：1165℃、4 h、140 MPa热等静压处理可有效消除铸态组织中的显微疏松和Laves相；与直接进行标准热处理相比，对合金进行热等静压处理后再进行固溶、时效处理，合金组织中γ″相数量增加，尺寸和分布更加均匀。由于显微组织的改善，合金室温和650℃抗拉强度和塑性均明显提高，650℃、620 MPa持久寿命由27 h延长至93 h，低周疲劳性能显著改善。%The post-processing technology of superalloy K4169 castings was studied. The effects of hot isostatic pressing (HIP) on the microstructure and mechanical properties were investigated by OM, SEM, TEM, tensile, stress rupture and fatigue tests. The results indicate that the microporosity and Laves phase existing in as-cast structure can be effectively eliminated by HIP at 1165 ℃, 140 MPa for 4 h. After further solution and aging treatment based on as-HIP,γ″phase increases in the amount and turns uniform in the size and distribution. Therefore, the strength and ductility increase at both room-temperature and 650 ℃, the stress rupture life at 650 ℃ and 620 MPa is enhanced to 93 h from 27 h and low cycle fatigue performance is improved notably.