Characterization of Cobalt Based CoCrMo Alloy Fabricated by Powder Metallurgy Route

Because of the increasingly utilization of CoCrMo alloy as biomaterial. The research is devoted toward characterization fabricated samples from gas atomized CoCrMo alloy powder by powder metallurgy route. The powder with average particle size 47.983 μm was ball milled for 8 hrs. at 175 rpm in stainless steel 304 SS container. Green compacts produced by uniaxial double pressing under (700,800,900,100,1100 &1200) MPa. Sintering was performed in electric resistance furnace in argon atmosphere at temperatures (1000, 1100, 1200 and 1300)°C for 2 soaking hrs for first group. Second group of samples were sintered at the same conditions but at (1200 °C) for different soaking times (1, 1.5, 2 & 2.5) hrs. The comparison of the chemical composition of the as received CoCrMo powder with that detected by SEM-Mapping for sintered compacts revealed high similarity between their values. Green density of the compacts is reached its greater value at (1000 MPa) which was 6.38 gm.cm^-3, while total porosity is reached its lowest value under the same pressure which was 22.51%. Micro-hardness results of the sintered compacts illustrated that the best sintering temperature and time were 1200°C and 2hrs respectively, where its value reached to the maximum (335 HV).