镍箔中间层厚度对GH4099合金固相扩散焊质量的影响

Effect of nickel interlayer thickness on solid-state diffusion bonding quality of superalloy GH4099

采用2,4和10μm镍箔作为中间层,在1 120℃/4 MPa/60 min焊接条件下,对高温合金GH4099进行固相扩散焊.采用SEM,EDS分析接头形貌演变、元素迁移,并利用拉伸试验测试其力学性能.结果表明,添加镍中间层能促进界面的孔洞闭合.随着镍层厚度由10μm降低至2μm,界面处出现晶粒共生现象,元素扩散更加均匀,焊缝析出较大尺寸的强化相,接头抗拉强度提高,2μm中间层接头平均抗拉强度达到1 180 MPa.但随着中间层减薄,接头性能对表面粗糙度敏感,拉伸过程中母材对中间层拘束作用使接头塑性变形受到抑制,断后伸长率反而降低.

This paper conducted solid-state diffusion bonding on superalloy GH4099,in which Nickel foil,in thickness of 2,4 and 10 μm,was inserted as interlayer. The welding process was implemented in vacuum at solution temperature1 120 ℃ under 4 MPa of axial compressive stress for 60 min of dwelling time. The microstructure and element migration and tensile property of the joint were measured by using SEM,EDS and tensile test. The results showed that,the adding of Nickel interlayer accelerated elimination of joint porosity. When Nickel interlayer thickness decreased from 10 μm to 2 μm,the grain symbiosis and chemical homogeneity were improved; whereas,the strengthening phases were precipitated more adequately from the joint,which contributed to the rise of tensile strength and the average strength of 1 180 MPa. However,the decrease of interlayer thickness made the joint performance sensitive to the surface roughness,meanwhile mechanical constraint provided by the base materials inhibited the plastic flow,resulting in the decrease of joint elongation.