Atomistic simulation for initiation of crystal slip deformation from surface of nanoscale copper single-crystal nanowires

• Published in: Computational materials science Vol. 226; p. 112246
• Main Authors: Kawai, Emi, Kubo, Atsushi, Umeno, Yoshitaka
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 25.06.2023
• Subjects: Active slip system; Critical resolved shear stress; Normal stress; Surface-step orientation; Active slip system; Normal stress; Surface-step orientation; Critical resolved shear stress
• ISSN: 0927-0256; 1879-0801
• DOI: 10.1016/j.commatsci.2023.112246

[Display omitted] •Slip initiation from a surface in nanometal is investigated by atomistic analysis.•Surface steps work as the trigger to induce slip deformation under tension.•An active slip system is determined to reduce the height of specific surface steps.•The active slip system is dependent on an orientation of surface steps.•Normal stress on the active slip plane affects the critical resolved shear stress. In nano/micrometer-scale materials, dislocations accounting for crystal slip deformation are introduced from the surface because of lack of pre-existing dislocations inside the materials. The dislocation emission from the surface must play an important role in the formation of dislocation network structures in the nano/micrometer-scale materials under cyclic loading, which should differ from that in macroscale materials. The purpose of this study is to investigate the effect of the atomic-level structure of surfaces on the initiation of crystal slip deformation. We create copper single-crystal nanowire models with different surface structures by varying the cross-section shape and crystal orientation. To observe the initiation of the slip deformation from the surface, we conduct atomistic simulations of tensile deformation for these models. We also discuss the effect of the surface structure on the critical shear stress for slip occurrence from the surface. Our analyses reveal that the orientation of surface steps and the normal stress on the active slip plane are important factors affecting the slip occurrence. Thus, the slip occurs in a slip system so as to reduce the height of a surface step. The active slip system is affected by the cross-section shape and crystal orientation because the slip system is dependent on the relationship between slip planes and the orientation of the surface step. Our results also suggest that the cross-section shape and crystal orientation affect the critical shear stress because of the difference of the normal stress on the active slip plane according to these factors.