Enhanced α → β phase transition of Ti–6Al–2Zr–1Mo–1V alloy by the electropulsing

Both the electropulsing-assisted treatment (EPAT) and traditional heat treatment (THT) were conducted to investigate the effect of the electropulsing on α → β phase transition in Ti–6Al–2Zr–1Mo–1V (TA15) alloy. The results showed that the electropulsing could significantly promote the α → β phase transition, and the promotion was related to the temperature and current density. When the critical value was exceeded, the enhancing effect of electropulsing on α → β phase transition was activated and enhanced with the increase in temperature and current density. EPMA and TEM-EDS techniques were used to detect the composition of EPAT samples. It was found that the electropulsing accelerated the diffusion of Mo and V atoms enriched within the β phase and grain boundaries, which promoted the nucleation and rapid growth of the β phase. Further analysis showed that the “local hot spots” and “electromigration” effect induced by electropulsing could reduce the energy required for atomic diffusion. When an electropulsing of 22 A/mm² passed through the TA15 alloy, the diffusion activation energy decreased from 120 to 95 kJ/mol.