Local decomposition induced by dislocation motions inside tetragonal Al2Cu compound: slip system-dependent dynamics

D Chen,X L Ma

doi:10.1038/srep03157

Abstract

Dislocations in a crystal are usually classified into several independent slip systems. Motion of a partial dislocation in monometallic crystals may remove or create stacking fault characterized with a partial of a lattice translation vector. However, it is recently known that motion of partial dislocations in complex structure, such as that inside an intermetallic Al2Cu compound, lead to a local composition deviation from its stoichiometric ratio and the resultant structure collapse. Here we report such a local decomposition behaviors are strongly dependent on slip system of dislocations. Under applied external stress, we have studied dislocation motion behaviors in the three independent slip systems of [001](110), [100]() and [110]() within tetragonal Al2Cu crystal by using molecular dynamics method. We found dislocation motions in all these slip systems result in local decomposition but their physical details differ significantly.

Highlights

Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, Wenhua Road 72, Shenyang 110016, China
We have studied dislocation motion behaviors in the three independent slip systems of [001](110), [100](010) and [110](110) within tetragonal Al2Cu crystal by using molecular dynamics method
We found dislocation motions in all these slip systems result in local decomposition but their physical details differ significantly

Summary

Introduction

It is recently known that motion of partial dislocations in complex structure, such as that inside an intermetallic Al2Cu compound, lead to a local composition deviation from its stoichiometric ratio and the resultant structure collapse. We report such a local decomposition behaviors are strongly dependent on slip system of dislocations. In the past decades, more and more experimental observations indicate that the small-sized second phase can be decomposed during plastic deformation, leading to degradation of material properties Such a decomposition of the strengthening particles under mechanical loading may unavoidably lead to a detrimental consequence. This work is expected to provide new information on dislocation motion behaviors in complex structures

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