Characterization of laser beam offset welding TiNi alloy and 304 stainless steel with different joining modes. (November 2020)

• Record Type: Journal Article
• Authors: Zhang, Yan; Zeng, HaoYuan; Zhou, JianPing; Xue, RuiLei; Sun, DaQian; Li, HongMei
• Is Part Of: Optics & laser technology. Volume 131(2020)
• Publication Date: 2020-11
• Subjects: TiNi alloy -- 304 stainless steel -- Welding -- Microstructure -- Filler metal; Optics -- Periodicals; Lasers -- Periodicals; Electronic journals; 621.366
• DOI: 10.1016/j.optlastec.2020.106372
• Languages: English
• ISSNs: 0030-3992

Abstract

Graphical abstract: Highlights: The possibility of laser welding-brazing for TiNi alloy-SS joint with Cu-base filler metal was studied. A composite joint based on two different joining mechanisms. 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: In this paper, laser welding of TiNi alloy and stainless steel (SS) dissimilar metal material with 38Zn-61Cu alloy as filler metal was carried. The results showed that the TiNi alloy and SS were joined by melting filler metal when the laser was concentrated in the SS side of the joint. One process was 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 1.2 mm, SS would not be completely melted in joint. During welding, the laser was focused near the TiNi alloy-SS interface, so that TiNi alloy and SS partially melted and diffusion welding process was realized at the TiNi alloy-SS interface, while element diffusion bonding occurred at the TiNi alloy-SS interface. No Ti-Fe intermetallic was detected in the joint. A diffusion weld was formed at the SS-TiNi alloy interface with the main microstructure of β-CuZn + Fe3 Zn7, β-CuZn and Ti2 Cu + TiNi. The joint fractured at the diffusion weld with the maximum tensile strength of 153 MPa.