Dislocations interaction induced structural instability in intermetallic Al2Cu

Qing Zhou,Fei Wang,Jian Wang,Amit Misra,Kewei Xu,Ping Huang

doi:10.1038/s41524-017-0030-2

Abstract

Intermetallic precipitates are widely used to tailor mechanical properties of structural alloys but are often destabilized during plastic deformation. Using atomistic simulations, we elucidate structural instability mechanisms of intermetallic precipitates associated with dislocation motion in a model system of Al2Cu. Interaction of non-coplanar <001> dislocation dipoles during plastic deformation results in anomalous reactions—the creation of vacancies accompanied with climb and collective glide of <001> dislocation associated with the dislocation core change and atomic shuffle—accounting for structural instability in intermetallic Al2Cu. This process is profound with decreasing separation of non-coplanar dislocations and increasing temperature and is likely to be operative in other non-cubic intermetallic compounds as well.

Highlights

Precipitation-hardening mechanisms have been widely applied for the development of high strength and ductile metallic alloys.[1]
We further examined dislocation climb for non-coplanar dislocation dipoles with different separations: h = 0.12 nm corresponding to one Al plane; h = 0.28 nm corresponding to three atomic planes; h = 1.13 nm corresponding to 11 atomic planes
The low formation energy associated with the creation of vacancies in the dislocation core region allows the occurrence of the climb

Summary

INTRODUCTION

Precipitation-hardening mechanisms have been widely applied for the development of high strength and ductile metallic alloys.[1]. As the separation L temperature accompanying the creation of vacancies This could is about 3 nm (corresponding to straining for 92 ps), Fig. 2b shows account for structural instability of intermetallic compounds the climb of partial dislocation 3 upwards for four atomic planes, during mechanical deformation.

RESULTS

DISCUSSION

METHODS