Enhanced kinetics of microstructural evolution in Ti–6Al–4V through electropulsing treatment

Abstract

The post-processing of Ti–6Al–4V, which has traditionally been conducted using furnace heat treatment (FHT), is crucial to attaining the optimum microstructure and mechanical performance. This study investigated the microstructural kinetics induced by the electropulsing treatment (EPT) of an extruded Ti–6Al–4V alloy from 50 to 400 s. The results were compared with the conventional microstructural evolution caused by FHT at the same temperature and duration. The remarkable energy efficiency enabled a rapid heating of EPT specimens. EPT enhances the kinetics of several aspects of microstructural evolution, such as phase transformation, static recrystallization, dislocation mobility, and the resultant suppression of grain growth. These phenomena arose from the promoted atomic diffusion due to the combination of the thermal and athermal effects of the electropulses. Grain refinement, amplified solid-solution hardening, and increased phase interfaces improved the microhardness of the EPT specimens. These results demonstrate the potential of EPT to facilitate favorable microstructural modifications in Ti–6Al–4V.

Keywords

• Ti-6Al–4V
• Electropulsing
• Microstructural evolution
• Bimodal microstructure
• Microhardness