热处理对GH4169电子束焊接头性能的影响研究

Study on Effect of Heat Treatment on Performance of GH4169 Electron Beam Welded Joint

采用电子束焊制备GH4169接头,并对接头进行固溶+双级时效处理,对比热处理前、后焊接接头常温(25℃)和高温(650℃)的拉伸性能及硬度分布,并采用光学显微镜(OM)、扫描电镜(SEM)、能谱仪(EDS)、X射线衍射仪分析接头微观组织、成分及断口形貌。结果表明,焊接接头经过热处理后室温抗拉强度提高61%,高温抗拉强度提高31%。热处理前后接头断裂皆为韧性断裂,但热处理后接头塑性显著降低。经固溶+时效热处理后的焊缝中δ相尺寸更加细小、分布弥散,且热处理过程焊缝中δ相发生部分溶解从而有更多的Nb元素形成强化相γ'',这使得焊接接头经热处理后抗拉强度得到明显提升。

The GH4169 joint was prepared by electron beam welding,and the joint was subjected to solid solution+double-stage aging treatment.The tensile properties and hardness distribution of the welded joint at normal temperature(25℃)and high temperature(650℃)before and after heat treatment were compared.The microstructure,composition and fracture morphology of the joints were analyzed by optical microscopy(OM),scanning electron microscopy(SEM),energy dispersive spectroscopy(EDS)and X-ray diffractometry.The results show that the tensile strength of the welded joint at room temperature increases by 61%and the tensile strength of the welded joint at high temperature increases by 31%after heat treatment.The fractures of the joints before and after heat treatment are ductile fractures,but the plasticity of the joint significantly reduces after heat treatment.The size ofδphase in the weld after the solution and aging heat treatment is finer and distributed dispersively,and theδphase in the weld is partially melted during the heat treatment process,so that more Nb elements form the strengthening phaseγ'',which makes the tensile strength of the welded joint significantly improve after heat treatment.