Tribological Behavior of a Heat-Treated Cobalt-Based Alloy

High temperature passive film on the surface of Co–Cr–Mo alloy and its tribological properties

“…10(a). These hard debris would impact between the surfaces or roll around freely, then cause threebody wear and surface fatigue during a short period, similar to that depicted by Wimmer et al [26,27]. In contrast, the worn surface of V950 sample is much smoother (Fig.…”

Effects of microstructures on the sliding behavior of hot-pressed CoCrMo alloys

“…The results of average coefficients of friction and wear factors for metal-onmetal pin-on-disc pairings are tabulated in Table 3 along with published data for a comparison. It was observed that under similar saline-lubricated environment, the average stable coefficients of friction for CoCrMo alloys are between $ 0.3 and 0.6 [3,17,32]. The common feature of the dynamic coefficients of friction was that it increases rapidly at initial contact, and then passes into a gradual increase, in which the latter phenomenon indicates stable contacts with prolonged sliding distances for all the pairings.…”

“…We have estimated approximately that the γ-ε phase transformation were 17% and 75% for LC-wrought (0.14% N) and Forged CoCr alloys (0.001% N), respectively [34]. The straininduced martensite tended to generate hard debris between surfaces [3], and the debris is hard to be compressed or deformed, to cause unstable and "noisy" coefficients of friction.…”

“…Mechanical properties of CoCrMo alloys, dependent on their microstructures, could be enhanced by solidsolution and/or surface hardening [3,4], manufacturing process and subsequent heat treatments [5,6], and precipitation (carbides, nitrides, etc.) hardening [7].…”

“…However, microstructures generated under various processes or heat treatments showed different responses to expectation, and if the matrix phase constitution and the type, morphology, size, distribution of the carbide and nitride precipitates are improperly controlled, they would accordingly result in loss of the desired properties or potential material failure [3] [14][15][16][17][18][19][20]. To date, few researches have been focused on the tribological properties of the HP CoCrMo alloys with various microstructures.…”