STUDY OF ROUGHNESS FORMATION INDUCED BY HOMOGENEOUS STRESS AT THE FREE SURFACES OF SOLIDS

Distributions of surface dislocations are used to investigate the free surface instability of a solid under compressive, tensile or shear stress. Calculation of the energy variation due to sinusoidal fluctuation of the surface allows the determination of the wavelength and the amplitude of the more probable roughness which can appear by surface or bulk diffusion or by plastic deformation. The role of surface tension is also studied; its main effect is to break the symmetry between tensile and compressive stress for the instability threshold.