Joining mechanism evolution of fusion welded TC4 titanium alloy/304 stainless steel dissimilar joint by GTAW

Abstract

Gas tungsten arc welding with a pure Cu filler wire was carried out to join the TC4 titanium alloy and 304 stainless steel. Filling pure Cu filler wire assisted with regulating welding current could effectively restrain the concentrated generation of Ti–Fe brittle intermetallic compounds. Three joining modes exist in the fusion welding titanium alloy and stainless steel. In the partial fusion welding mode, the TiCu phase decreased and the fine granular τ₂ phase formed in the Ti/Cu interfacial zone, simultaneously, the molten zone consisted of a Cu solid solution and α-(Fe, Cr) phase formed at the Cu/Fe interface, resulting in mechanical interlocking effect and consequent high tensile strength of 363 MPa. Increasing the welding current would lead to the alloying of Ti_xCu_y phases, and then enhance the Ti/Cu interface.

KEYWORDS:

• Titanium alloy/stainless steel dissimilar joint
• interfacial joining mechanism
• intermetallic compounds
• microstructure
• tensile strength

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was financially supported by the National Natural Science Foundation of China [grant number 52105389] and the Fundamental Research Program of Shanxi Province [grant number 20210302124113].