Correlation between wear resistance and subsurface recrystallization structure in copper

Wear of conventional metallic materials involves various complex solid state processes of which the dominant process is elusive. From a thorough experimental investigation on the worn subsurface structure evolution in pure copper specimens with various microstructures, we conclude that the transformation from the subsurface dynamic recrystallization (DRX) structure into the top nanostructured mixing layer (NML) is the most important process which could determine the wear rate. A pronounced correlation is identified that wear rate increases significantly with an increasing grain size or a decreasing hardness of the DRX structure adjacent to the NML. This result points out an effective approach to make materials better against wear by stabilizing the deformed structure against DRX.