Prediction of Weld Pool Profile of Dissimilar Laser Weld Between NiTi/Ti6Al4V Via Different Interlayers

Abstract

NiTi and Ti6A14V were materials with superior properties and shared application areas while joining them with fusion weld stayed as a challenge. Solidification of excessive brittle Ti2Ni intermetallic phases and development of microcracks are the main challenges of creating weld between these alloys. Therefore, Pulsed mode welding with an offset laser was employed to develop a dissimilar weld between NiTi and Ti6A14V with the aid of Cobalt and Zirconium interlayers. The involvement of interlayers along with laser offsetting improved the mechanical properties of the joint. Tensile strength of the joints with Zirconium and Cobalt interlayers reached a maximum of 319MPa and 275MPa with a percentage elongation of 1.53% and 1.47%, while the weld without interlayer was limited to 148MPa and 0.8%. A thermal transient model with a Modified Three-Dimensional Conical volumetric heat source was employed to predict the temperature distribution and Weld-pool shape in dissimilar NiTi/Ti6Al4V weld with and without the interlayers, and a good agreement was evident between simulated and experimental results.