Dislocations interaction induced structural instability in intermetallic Al2Cu

Abstract

Intermetallics: dislocation climb promotes precipitate dissolution Instead of gliding, dislocations in intermetallic precipitates interact to climb, leaving defects behind. Qing Zhou and colleagues at Xi’an Jiaotong University in China and their collaborators in the United States of America used molecular dynamics simulations to investigate the interactions of dislocations in intermetallic precipitates in aluminium-copper during deformation. They showed that instead of traditional glide, dislocations that do not lie on the same plane can interact by climbing then gliding along a new atomic plane without cancelling each other out, leaving vacancies behind. This defect creation happened faster at higher temperatures, creating extended dislocation cores and vacancy clusters that could facilitate precipitate dissolution. Research into intermetallic stability during deformation may thus help us avoid failure of alloys strengthened with precipitates.