Influence of current pulsing on microstructure and mechanical properties of Ti–6Al–4V TIG weldments

The present study has investigated the influence of current pulsing on the structure and mechanical properties of Ti–6Al–4V tungsten inert gas (TIG) weldments. Autogenous full penetration bead on plate TIG welds were made with and without direct current pulsing. Microstructural observations and evaluation of hardness, tensile and fatigue properties of the weldments were made in different conditions: as welded and post-weld heat treatment (PWHT) conditions (PWHT was done at 700 and 900°C). Current pulsing resulted in slight refinement of prior β grains, leading to better tensile strength, ductility and fatigue lives of weldments in the as welded condition. In the case of weldments subjected to PWHTs, the pulsed weldments exhibited inferior fatigue lives compared with the unpulsed weldments. The PWHT done at 900°C resulted in inferior fatigue lives of weldments compared with that done at 700°C.