Research on the Structural, Mechanical and Corrosion Tribological Properties of CoCrMo and CoCrMoW Alloys in Calf Serum Solution

Abstract

In order to clarify the corrosion friction behavior and corrosion wear resistance mechanism of CoCrMo and CoCrMoW alloys in calf serum solution, CoCrMo and CoCrMoW alloys were prepared using the vacuum melting technique, and the microstructure, mechanical and corrosion tribological properties of the two alloys were investigated by means of scanning electron microscopy(SEM),energy-dispersive spectroscopy(EDS) , transmission electron microscope(TEM), X-ray diffraction(XRD), compression mechanical performance experiments and corrosion wear tests.Results showed that the two alloys were composed of γ-Co and ε-Co, and the microstructure was dominated by equiaxial crystals.CoCrMo alloy exhibited excellent compressive mechanical properties and good corrosion resistance in calf serum solution,while pitting corrosion occurred in the CoCrMoW alloy.The two alloys showed good corrosion tribological properties in calf serum solution, with friction coefficients and wear rates of 0.11 ～0.21 and 1.01×10－6 ～2.46×10－6 mm3/(N·m), respectively.The friction coefficients of the two alloys decreased with the increase in load and frequency, and the stability of real-time friction coefficients increased.At low loads, the corrosive wear resistance of the alloys increased with frequency, and their wear mechanisms were dominated by abrasive wear.At high loads, the wear rate of the alloys increased with frequency,and abrasive wear and corrosive wear coexisted.Overall,the corrosion wear resistance of CoCrMo alloy was better than that of CoCrMoW alloy, which was mainly due to the better compressive mechanical properties and corrosion resistance of CoCrMo alloys.

Keywords

• cocrmo series alloys； microstructure； mechanical properties； corrosion tribological properties； corrosion and wear resistance mechanism