Cell structure formation in a two-dimensional density-based dislocation dynamics model

Materials Theory

article

Wu, Ronghai¹  Zaiser, Michael² 

[1] School of Mechanics, Civil Engineering and Architecture, Northwestern Polytechnical University;Department of Materials Science, Friedrich-Alexander Universität Erlangen-Nürnberg

关键词: Continuum dislocation dynamics;    Dislocation patterning;    Scaling invariance;    Strain hardening;   

DOI  :  10.1186/s41313-020-00025-x

学科分类：社会科学、人文和艺术（综合）

来源: Springer

【 摘 要 】

Cellular patterns formed by self-organization of dislocations are a most conspicuous feature of dislocation microstructure evolution during plastic deformation. To elucidate the physical mechanisms underlying dislocation cell structure formation, we use a minimal model for the evolution of dislocation densities under load. By considering only two slip systems in a plane strain setting, we arrive at a model which is amenable to analytical stability analysis and numerical simulation. We use this model to establish analytical stability criteria for cell structures to emerge, to investigate the dynamics of the patterning process and establish the mechanism of pattern wavelength selection. This analysis demonstrates an intimate relationship between hardening and cell structure formation, which appears as an almost inevitable corollary to dislocation dominated strain hardening. Specific mechanisms such as cross slip, by contrast, turn out to be incidental to the formation of cellular patterns.

【 授权许可】

CC BY