Atomic simulations of twist grain boundary structures and deformation behaviors in aluminum

Qing Yin,Rajiv Mishra,Zhiqiang Wang,Zhenhai Xia

doi:10.1063/1.4975042

Abstract

The structures and behaviors of grain boundaries (GBs) have profound effects on the mechanical properties of polycrystalline materials. In this paper, twist GBs in aluminum were investigated with molecular dynamic simulations to reveal their atomic structures, energy and interactions with dislocations. One hundred twenty-six twist GBs were studied, and the energy of all these twist GBs were calculated. The result indicates that &lt;001&gt; and &lt;111&gt; twist GBs have lower energy than &lt;101&gt; twist GBs because of their higher interplanar spacing. In addition, 12 types of &lt;001&gt; twist GBs in aluminum were chosen to explore the deformation behaviors. Low angle twist GBs with high density of network structures can resist greater tension because mutually hindering behaviors between partial dislocations increase the twist GB strength.

Highlights

Grain Boundaries are common in polycrystalline materials and strongly influence the deformation responses and mechanical properties of materials
Grain boundaries are important to the deformation mechanism of polycrystalline materials,[4] including GB migration,[5] GB diffusion, dislocation nucleation around grain boundaries,[6,7,8] and interaction of lattice dislocations and grain boundaries.[9,10,11,12]
Much research related to grain boundary has been conducted by using molecular dynamics (MD) simulation; for example, dislocation nucleation from GBs in aluminum by Spearot et al.,[14] behaviors about tilt GBs under tensile force by Tschopp et al.,[15,16,17,18,19] and twist GB energy analysis by Zhang.[20]

Summary

INTRODUCTION

Grain Boundaries are common in polycrystalline materials and strongly influence the deformation responses and mechanical properties of materials. A fundamental understanding of structures and deformation behaviors of grain boundaries is necessary to develop materials design principles to improve the mechanical properties of polycrystalline materials. Grain boundaries are important to the deformation mechanism of polycrystalline materials,[4] including GB migration,[5] GB diffusion, dislocation nucleation around grain boundaries,[6,7,8] and interaction of lattice dislocations and grain boundaries.[9,10,11,12] Before studying these GB behaviors, the basic properties of GBs should be investigated.

COMPUTATIONAL MODELS AND METHODS

Twist GB structure and energy

Twist GB deformation behaviors

CONCLUSION