Discrete dislocation dynamics simulations of surface induced size effects in plasticity

作者：Han CS^*; Hartmaier A; Gao HJ; Huang YG

来源：Materials Science and Engineering A-Structural Materials Properties Microstructure and Processing, 2006, 415(1-2): 225-233.

DOI：10.1016/j.msea.2005.09.075

• plasticity
• discrete dislocation dynamics
• size effects
• surface effects

Experiments have shown that the presence of free surfaces may induce harder as well as softer deformation behaviors in a crystalline solid. In order to shed some light on these apparently contradictory findings, two-dimensional discrete dislocation dynamics simulations are performed to investigate the surface induced size effects. The simulations indicate that, depending on the surface density of dislocation sources, a free surface may act either as a dislocation sink or as a net dislocation source, and can accordingly exert opposite effects on dislocation density over a boundary layer thickness of up to 500 nm into the bulk. This finding provides a possible explanation for the apparent contradictions in experimental observations.

• 出版日期2006-1-15
• 单位中国科学院金属研究所