A quantitative study of the effect of surface texture on plasticity induced surface roughness and dislocation density of crystalline materials

Abstract

Microscale simulations are used to study the effects of the surface texture and plastic deformation on surface roughness and dislocation density, which are important parameters controlling some surface physical properties such as electron work function (EWF) and phonon emission of crystalline materials. The results of the simulations on superconducting niobium show that the intensity and the components of the surface texture have significant effects on the plasticity induced surface roughness and dislocation density. A weak surface texture develops a rough surface after plastic deformation, which is due to the different plastic “shear rates and directions” behavior in the grains with different orientations. Some grains with specific orientation experience more plastic deformation, and therefore develop an intragrain surface roughness due to the development of microtexture and inhomogeneous plastic deformation inside the grain. Due to an inhomogeneous plastic deformation, the dislocation density not only is different in the grains with different orientations but also is inhomogeneous within a grain. Therefore, it may be possible to design surface texture to obtain optimal EWF and minimal electron emission and control surface roughness and dislocation density in polycrystalline materials.