Influence of Pd Addition of CoCrMo Biomedical Alloys on the Microhardness Behaviour

CoCrMo alloys are often used as the material for metal artificial joint because of their high corrosion resistance and mechanical properties. In this study CoCrMo alloys having different palladium amount of produced by investment casting method. Scanning electron microscopy, X-ray diffraction method and indentation tests were used to examine the mechanical properties of the alloys. Indentation experiments were carried out using Vickers indenter that the loads range from 0.245 to 9.8 N. The alloys exhibit significant load-dependence (i.e., indentation size effect). Meyer's law, proportional specimen resistance model, and Hays-Kendall model were used to analyze the load dependence of the hardness. As a results for load-independent determination of the CoCrMo alloys, the Hays-Kendall model is found to be more effective than the proportional specimen resistance model and microhardness values decreases with increase of the Pd content.