Butt laser welding of TC4 Titanium alloy and 304 stainless steel with Ag-base filler metal based on a hybrid connection mechanism. (April 2020)

• Record Type: Journal Article
• Authors: Zhang, Yan; Bi, YuanBo; Zhou, JianPing; Sun, DaQian; Gu, XiaoYan
• Is Part Of: Optics & laser technology. Volume 124(2020)
• Publication Date: 2020-04
• Subjects: TC4 Ti alloy -- 304 stainless steel -- Welding -- Microstructure -- Filler metal -- Numerical simulation; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2019.105957
• Languages: English
• ISSNs: 0030-3992

Abstract

Highlights: The possibility of laser welding-diffusion bonding for Ti alloy-SS joint with Ag-base filler metal was studied. A composite joint based on two different joining mechanisms. The unmelted SS acted as a barrier to mixing of the base materials. The unmelted SS and filler metal prevented the formation of brittle Ti-Fe intermetallics in the joint. Abstract: Laser welding of TC4 Titanium (Ti) alloy to 304 stainless steel (SS) has been applied using Ag45-Cu30-Zn25 alloy as filler metal. Microstructures of the joints were studied using scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). Mechanical properties of the joints were evaluated by performing tensile tests. The temperature field and stress field distributed in laser welding based on SS-Ti alloy joint were dynamically simulated using the ABAQUS in this study. A new welding process for SS-Ti alloy joint was introduced on the basis of the controlling the formation of Ti-Fe intermetallics in the joint. One pass welding involving creation of a joint with one fusion weld and one diffusion weld separated by remaining unmelted SS. When laser beam on the SS side was 1.6 mm, SS would not be completely melted in joint. Through heat conduction of unmelted SS, the atomic diffusion occurred at the SS-Ti alloy interface. A diffusion weld was formed at the SS-Ti alloy interface with the main microstructure of α-Cu + Fe3 Zn2, AgZn3 + CuZn, Cu4 Ti + Ti2 Zn3 and Ti2 Cu + TiCu. The joint fractured at the diffusion weld with the maximum tensile strength of 284 MPa. By comparing the simulation results with the corresponding experimental findings, the validity of the numerical model is confirmed.