Microstructure and mechanical properties of laser welded Ti-10V-2Fe-3Al (Ti1023) titanium alloy

The microstructure, microhardness, tensile properties, and fracture characteristics of the laser welded Ti-10V-2Fe-3Al(Ti1023) titanium alloy in the as-welded condition were examined. The mechanical properties were related to the microstructure development across the weld. In the base material (BM), the primary c phase with spherical and lath morphologies was dispersed in the beta matrix. The volume fraction of the alpha phase in the heat affected zone (HAZ) decreased to some extent compared to the BM as a result of its partial dissolution and/or transformation to the beta phase. In the fusion zone (FZ), primary alpha phase was completely transformed to the beta phase. The BM exhibited a higher hardness than HAZ and FZ due to a higher volume fraction of the primary alpha phase, which is harder than beta phase. The yield strength (YS) and ultimate tensile strength (UTS) of the weldments were somewhat lower than those of the BM due to the presence of a softer phase in the FZ and a lower volume fraction of the alpha phase in the HAZ. Also, the presence of porosity, undercut, concavity, and coarse columnar beta grains in the FZ contributed to lower YS, UTS, and total elongation in the weldments in comparison to the unwelded material. Examination of the fracture surface in the weldment tensile samples indicated a mixed brittle and ductile fracture mode. (C) 2020 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org,licenses/by-nc-nc1/4.0%).