Abstract: The wear properties of ultrafine-grained (UFG) Cu samples of different purities were investigated in comparison with the coarse-grained (CG) Cu. The UFG Cu samples, prepared by means of plastic deformation via quasi-static compression, exhibit an enhanced wear resistance relative to the CG Cu samples. For both the UFG and the CG Cu samples, wear volumes increase at higher purities. A steady state worn subsurface structure was formed in each sample after sliding for 60 min, consisting of a heavily deformed nanostructured mixing layer (NML) on top of a continuous dynamic recrystallization (DRX) layer. A pronounced correlation is identified that wear volume increases monotonically with an increasing grain size of the DRX layer. The impurity level of the Cu samples has an obvious in°uence on the DRX grain sizes, which in turn determines the wear resistance of the Cu samples.

Key words: Ultrafine grained copper , Wear resistance , Impurity , Subsurface microstructure , Dynamic recrystallization