Gradient microstructure in tantalum formed under the wear track during dry sliding friction

Abstract The formation of a gradient microstructure in pure tantalum under the wear track of dry sliding wear test was investigated. Materials were exposed to different amounts of Severe Plastic Deformations, and the evolution of the microstructure and mechanical properties as well as the wear behavior were studied in this work. Results showed that the friction coefficient and the wear were independent of the initial microstructure and hardness of the material, but the depth of the gradient layer under the wear track depended on the history of the treatment which was previously applied to the material. Furthermore, it was revealed that imposing an excessive amount of deformation on the material caused the delamination and initiation of cracks in the sublayer of the wear track.