Dry sliding wear of Cu-Be alloys

The tribological behaviour of two Cu-Be alloys was investigated under dry sliding conditions against an AISI M2 steel counterface. The first alloy, Cu-Be1, was characterized by a hardness of 390 HV and a thermal conductivity of 106 W/mK, whereas the second one, Cu-Be2, had a lower hardness, 270 HV, and a higher thermal conductivity, 208 W/mK. At low loads, wear was metallic in nature. The Cu-Be1 alloy displayed the lowest wear rate, as expected. As the applied load was increased, however, the wear rate of the Cu-Be1 alloy increased, whereas the wear rate of the Cu-Be2 alloy was found to decrease and, in particular, to become lower than that of the Cu-Be1 alloy. A transition in the wear mechanism from metallic wear to tribo-oxidative wear was observed as the applied load was increased. The results were explained in terms of the characteristics of the tribological layer, which forms during sliding on the surface of the Cu-Be specimens.