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.