Bauschinger effect in wear of Cu-40Zn alloy and its variations with the wear condition

The performance of a Cu-40Zn alloy during unidirectional and bidirectional (forth-and-back) sliding wear processes was investigated. It was observed that the alloy was worn less during bidirectional wear than during unidirectional wear. The mass loss of alloy decreased as the number of sliding-direction reversals was increased; correspondingly, hardness of the worn surface decreased after initial increase. Illustrative finite element modeling showed that bidirectional sliding resulted in lower residual stress than the unidirectional sliding. It appears that Bauschinger effect played a role during the bidirectional wear processes. Such a role was dependent on the sliding speed and applied load, which influenced the wear behavior through alternating plastic deformation path and cracking events. Mechanisms responsible for the observed phenomena are discussed.