Process optimization and friction and wear properties of CoCrWMo alloys fabricated by selective laser melting

Process parameters of the CoCrWMo alloys fabricated by selective laser melting (SLM) were optimized, and the friction and wear properties of the alloy samples prepared under the optimal process parameters were analyzed. The results show that, the optimal parameters of selective laser melting are as followed: the laser power is 280 W, the scanning speed is 800 mm·s⁻¹, the layer thickness is 0.03 mm, the scanning space is 0.10 mm, and the scanning strategy is rotation method (15° rotation between adjacent layers). The laser energy density is 117 J·mm⁻³, the relative density of the prepared samples is 99.4%, the top surface roughness (Ra) is 4.98 μm, the microhardness is HV 386, the tensile strength is 984 MPa, the yield strength is 663 MPa, and the elongation is 12.9%. During the dry friction, the average friction coefficient of the prepared CoCrWMo alloys decreases with the increase of the applied load, while the average wear rate increases first and then decreases under the influence of the strain-induced martensite transformation during the wear process. The main wear mechanisms are abrasive wear and adhesive wear.