The effect of Zn interlayer on microstructure and mechanical performance during TIG overlap welding-brazing of Al to Ti

Abstract

Tungsten inert gas welding-brazing technology was investigated to achieve the sound joining of Al-Ti alloys with the addition of Zn interlayer. Experiment results show that the Zn interlayer was beneficial to enhance the wettability of weld metal on Ti alloy substrate and improve the weld appearance. With low heat input, a Zn rich layer was observed near the brazing zone. As the heat input increased, TiAl 3 phase was generated in fusion area and the morphology of interfacial brazing layer changed from lamellar to serrate. With the welding current increased to 85A, the micro hardness of fusion area increased and presented a great fluctuation owing to the excessive formation of TiAl 3 phase. Under the optimal welding current of 75A, the sound Al-Ti weldment with the maximum tensile strength of 175MPa was obtained. Eventually, the improvement mechanism of wettability was investigated.

Study on Laser Overlap Welding of Titanium/Aluminum Dissimilar Metals Based on Niobium Microalloying

“…They discovered that the use of Zn as an intermediate layer did not significantly impact the stirring zone of the joints. Li et al [17] created a lap joint between the TC4 titanium alloy and 5052 aluminum alloy using Zn as an intermediate layer in a tungsten inert gas welding process. They theorized that the use of a Zn layer could enhance the wettability of the weld seam on the titanium alloy base and detected a Zn-rich layer in the brazing zone.…”