Electric pulse improving the plasticity of the HAl66-6-3-2 alloy by promoting the formation of specific oriented texture

Abstract

Electric pulse treatment (EPT) effectively enhances material plasticity but typically compromises strength, and the combined mechanisms of pulsed current on dislocation evolution and grain rotation remain unclear. Here, HAl66-6–3-2 alloy was subjected to EPT, and the results revealed that the EPT sample achieved an increase in plasticity without compromising the strength, with an elongation rate enhancement of 69.89 %. The changes in performance are mainly attributed to three aspects: grain refinement, slight decrease in dislocation density, and the formation of strong {632}<223> texture during the EPT. Unlike the untreated (UT) samples with entangled dislocations, under the coupling effect of Joule heating and non-thermal effect, the dislocations in EPT samples exhibited directionality, primarily composed of a series of parallel dislocation pairs. The formation of the strong {632}<223> texture primarily relied on grain boundary migration and grain rotation, with both Joule heating and non-thermal effect facilitating rapid grain boundary migration. At low-angle grain boundaries, the pulsed current facilitated grain rotation, transforming low-angle grain boundaries in the β phase into high-angle grain boundaries. The study demonstrates EPT can promote the movement of atoms and regulate the microstructure, which is of great significance for the subsequent control of alloy properties.