Analysis of the microstructure and microhardness of rotary friction welded titanium (Ti‐6AL‐V4) rods

Abstract: This paper presents the evolution of mechanical properties in Ti6Al4V rods welded by rotary friction welding. This is evaluated by monitoring the microstructure and micro hardness changes resulting from the welding. 16 mm diameter Ti6Al4V rods were joined by rotary friction welding utilizing different process parameter settings, namely; axial force, rotational speed and upset distance. The microstructure and micro hardness analysis were observed on each of the weld zones/regions. The micro hardness results revealed higher hardness on the weld zone and low hardness on the heat‐affected zone when compared to the parent material. The higher axial force resulted in higher hardness in the weld zone because of more friction and hence higher heat input which led to refined microstructure. Microstructure characterization for the different weld zones due to varying process parameters is also discussed