电镀阻隔层对钛/钢电子束焊接接头性能的影响

采用电子束熔化焊、电子束阻隔焊和电子束阻隔熔-钎焊方法来实现钛合金与不锈钢异种金属之间的连接。研究发现钛合金与不锈钢连接界面处产生的脆性金属间化合物是影响接头性能的关键因素。采用电子束直接熔化焊和阻隔熔化焊钛合金和不锈钢时,接头界面会产生贯穿性裂纹导致焊缝直接断裂。电子束阻隔熔-钎焊中利用熔化的不锈钢润湿未熔化的钛合金母材,并采用Ag、Cu作为中间层添加元素,在结合界面处形成了很好的阻隔屏障,减少了Ti/Fe界面的金属间化合物的产生,减缓了应力,实现了钛合金与不锈钢的冶金结合,接头抗拉强度约为100 MPa。电子束阻隔熔-钎焊得到的钛合金/不锈钢异种金属焊接接头焊缝正反面成形良好,X射线探伤未发现裂纹和气孔缺陷。

Effect of Isolation Coatings on Mechanical property of Electron Beam Welding Joint of Titanium Alloy to Stainless-steel

Electron beam welding, electron beam isolation welding and electron beam isolation welding-brazing for the dissimilar combination of titanium alloy and stainless steel will be studied in this project. The present results show that the brittle intermetallic compound formed in the welding process is the key factor to influence the joint properties. The penetrated crack is formed in electron beam welding and electron beam isolation welding process directly leading to the joint unsuccessful. In electron beam isolation welding-brazing process, the joints has the characters of welding and brazing and the metallurgically bonded joint is achieved without melting the titanium alloy sheet. Ag and Cu as filler material exhibit good isolation layer which helps minimizing the formation of Ti/Fe intermetalics, aslo has an relaxation effect on the residual stress of the weld. The interalloying of dissimilar materials well controlling, a reaction zone is gained on the interface. The maximum tensile strength of titanium alloy/stailess-steel is up to 100MPa. The welded seams are good shape as well as the back of the joints and there is no crack and detected porosity in the joints through X-ray inspection.