Reheat cracking in Ti2AlNb alloy resistance spot weldments

Serious reheat cracking susceptibility was found in Ti2AlNb alloy resistance spot weldments and the cracking mechanism was investigated in this work by means of hot ductility test and microstructure analysis. The results indicated that the precipitation of hardening phase (O phase) together with the residual stress have led to cracking during post-weld heat treatment in Ti2AlNb alloy resistance spot weldments. To prevent the reheat cracking, rapid heating schedule or mechanical stress relieving method was proposed and verified.

► Serious reheat cracking was detected in Ti2AlNb alloy resistance spot weldments.
► The cracking mechanism was proposed.
► Two effective methods were proposed to prevent the occurrence of reheat cracking.