This paper presents the investigation of the surface roughness on the material dislocation using bonded interface technique. The influence of the surface roughness on three different materials was focused on this study. By using the bonded interface technique, the half-specimens of stainless steel, aluminium and brass were bonded and microindentations were conducted on the bonded interface surfaces with roughnesses ranged from 0.05 to 0.37 µm. The results revealed that the increase of surface roughness induced an exponential decrease in material dislocation in vertical direction beneath the permanent indent. Using Nix-Gao model, rougher surface produced higher load independent hardness which the materials experience the hardening effect. From the observation on the plastic deformation zone, the shear bands of harder material stainless showed limited material dislocation compared to softer material aluminium and brass.
