Influence of Zr addition on TIG welding-brazing of Ti-6Al-4V toAl5A06

TIG welding-brazing of Ti-6Al-4V to Al5A06 alloys with pure Al and Al-Cu-Zr fillers was investigated. The Zr and Cu additions enhanced the spreadability of Al-based fillers on Ti-6Al-4V substrate under TIG heating condition, and a sound Ti/Al dissimilar butt joint was obtained. Influenced by Zr addition, a discontinuous TiAl3 layer with a thickness of 2-4 μm was observed at the Ti/seam interface under a low heat input condition, which was replaced by TiAl3+L-(Ti,Zr)Al3+H-(Ti,Zr)Al3 multi-sublayers when a high heat input was adopted. The joint with Al-Cu-Zr filler has higher tensile property and wider processing parameters than that with pure Al filler. The largest tensile strength of the joint produced by Al-Cu-Zr filler reaches 284 MPa up to 85% of base Al5A06 alloys, and the fracture occurred by quasi-cleavage mode at the TiAl3 sublayer. Zr addition was favorable to enhance the spreadability on Ti substrate, and the welding processing parameters were broadened by the presence of Zr addition.