Effects of Mn5Si3 Content on the Wear of Copper Alloys

Copper alloys containing the hard phase would be expected to have high wear resistance. In this study, the wear of Cu, Cu-Sn, Cu-Zn and Cu-Al alloys with and without Mn5Si3 (hard phase) has been investigated. Manganese silicide (Mn5Si3) is formed in the solidification of copper alloys containing Mn and Si. The results obtained are summarized as follows: (1) In hypoeutectic, wear is increased by the existence of eutectic Mn5Si3 particles. It is considered that the decrease in wear resistance is attributed to eutectic Mn5Si3 which plays the role of crack propagation source after being transfered from the metal matrix to sliding surface as a result of the plastic flow of the matrix. (2) In hypereutectic, wear resistance is increased by the existence of primary Mn5Si3 crystals. It is suggested that the primary Mn5Si3 crystals play a role of piles which suppress the plastic flow of the metal matrix and its adhesion to an opponent.