Aluminum to titanium laser welding-brazing in V-shaped groove

Within defined window of operational parameters, statistically important factors that influenced the strength of T40 to AA5754 joints in V groove configuration were Si content in the filler metal and groove opening angle on T40 side. The best quality joint showed joint coefficient of 90% (or 200 MPa of apparent UTS). Tensile strength of the joints was found to be determined by the proportion between well-developed and under-developed reaction zones of T40/melted zone interface. The formation of 2-25 μm thick Si-rich interlayers composed by Ti5Si3 and τ2 proved to enhance the strength of brazed interface. The creation of very thin (<0.5 μm) Si-rich layers at the bottom of the groove was found not sufficient to establish mechanical continuity of the joint and thus should be avoided.