Studies on Effect of Parent Metal Condition on the Room Temperature Mechanical Properties of Ti6Al4V Friction Welds

The influence of parent metal condition on the microstructure and mechanical properties of friction welds of Ti6Al4V alloy has been investigated. Welds are observed to contain predominantly martensite. Stress relieving results in improvement in the strengths of α + β and β treated parent metal and their welds. β welds are observed to contain coarser prior β grains. Studies reveal that welds of α + β solution treated parent metal exhibit higher strength than all the other welds. In plain tensile tests, the location of failure is away from the welds in all the conditions, suggesting that the welds are stronger than their respective parent metals. Parent metal in α + β and β solution treated conditions is observed to respond to stress relieving such that, hardness is improved after stress relieving. Stress relieving results in reduced ductility and improvement in the strength of the welds. Notch tensile strength of the welds is observed to be higher than their parent metals and stress relieving results in further improvement. The notch tensile ratio of the welds has been observed to be ~1.4 in all the conditions indicating that the welds are not notch sensitive.