Sintering Effects on the Microstructure and Mechanical Properties of CoCrMo Alloy

Cobalt chromium molybdenum (CoCrMo) alloy is widely used in artificial hip and knee joints because of their excellence corrosion and wear resistance, as well as good mechanical properties and biocompatibility. This study investigates the effect of sintering temperature on the microstructure and mechanical properties of CoCrMo using powder metallurgy technique. CoCrMo powder was mixed with zinc stearate and then put into the shaker mixer at 65 rpm for 3 hours. The powder was then compacted at a pressure of 18T using an automated hydraulic press and sintered at a temperature in the range of 1200 – 1400 °C under 95 Vol% N2/ 5 Vol% H2 atmosphere. The microstructure, physical and mechanical properties of the samples are analyzed using scanning electron microscopy (SEM), Vickers’s microhardness tester and transverse rupture strength (TRS). The study reveals that the density, hardness and strength of CoCrMo samples increase as sintering temperature increases.