The effect of 3 wt.% Cu addition on the microstructure, tribological property and corrosion resistance of CoCrW alloys fabricated by selective laser melting

摘要

Microstructure, tribological property and corrosion resistance of orthopedic implant materials CoCrW-3 wt.% Cu fabricated by selective laser melting (SLM) process were systematically investigated with CoCrW as control. Equaxied gamma-phase together with the inside {111} 112 type twin and platelet epsilon-phase was found in both the Cu-bearing and Cu-free alloys. Compared to the Cu-free alloy, the introduction of 3 wt.% Cu significantly increased the volume fraction of the epsilon-phase. In both alloys, the hardness of epsilon-phase zone was rather higher (similar to 4 times) than that of gamma-phase zone. The wear factor of 3 wt.% Cu-bearing alloy possessed smaller wear factor, although it had higher friction coefficient compared with Cu-free alloys. The epsilon-phase in the CoCr alloy would account for reducing both abrasive and fatigue wear. Moreover, the Cu-bearing alloy presented relatively higher corrosion potential E-corr and lower corrosion current density I-corr compared to the Cu-free alloy. Accordingly, 3 wt.% Cu addition plays a key role in enhancing the wear resistance and corrosion resistance of CoCrW alloys, which indicates that the SLM CoCrW-3Cu alloy is a promising personalized alternative for traditional biomedical implant materials.