Orientation dependence of dislocation structure in surface grain of pure copper deformed in tension

Abstract

Orientation dependence of dislocation structure in surface grain of pure copper deformed in tension was investigated and compared with that in bulk grain. Dislocation cell structure is dominated in [100]-[100] surface grain at a given strain, which follows the same rule with its bulk counterpart. For [110]-[110] and [110]-[111], bulk grains in a strain range are dominated by dislocation cell block structures, while surface grains with the same lattice rotation history can develop into either a cell block structure or dislocation cell/tangle structure, depending on the grain geometry and strain level. Dislocation structure evolution is postponed in surface grains due to the image force of the surface. The results indicate that dislocation evolution in surface grain of pure copper is not only orientation-dependent, but also strongly related with grain geometry.