Computation and validation of weld pool dimensions and temperature profiles for gamma TiAl

Previous research by the authors has shown that the welding current has a strong effect on the weld properties and microstructures of gamma TiAl. This article presents the results of experimentally measured and theoretically predicted temperature profiles of gas tungsten arc (GTA) welded gamma TiAl for welding currents of 75 and 100 A. The GTA welding model used in this study accounts for the fluid flow in the weld pool as well as conductive, convective, and phase change heat transfer processes in the solid, liquid, and mushy regions of a metal. The computed temperature fields predicted that as the welding current is increased, the maximum temperature reached in the weld pool also increases. Experimental validation of the computed temperature fields was determined by placing thermocouples at three locations on the specimen, to record the temperatures during welding using computer-based data acquisition hardware and software. The agreement between theoretical predictions and measurements was reasonably good, which provided a direct validation of the model.