Fracture Mechanism of CoCrMo Porous Nano-composite Prepared by Powder Metallurgy Route

The main aim of this research was to find the mechanism for the failure of the CoCrMo porous nano-composite by characterizing microstructural changes and fractured surface after compression test. For this purpose, porous nano-composites were prepared with the addition of bioactive glass nano-powder to Co-base alloy with 22.5% porosity by the combination of space-holder and powder metallurgy techniques. The micrographs of samples showed that porous nano-composites had the micro and macro pores including open and closed pores. The observed fracture surface in the triple conjunction of sintered powders indicated a complex of intergranular and transgranular fracture mechanisms. The brittle carbide phase related to the higher solute content (Cr and Mo) precipitated at grain boundaries, leading to the intergranular fracture mechanism and transgranular mechanism that was due to the phase transformation during compression test.