Semi-solid Sintering of Ti6Al4V/CoCrMo Composites for Biomedical Applications

A composite of Ti6Al4V reinforced with CoCrMo particles is fabricated by conventional powder metallurgy and semi-solid sintering. Composites are fabricated by mixing 20% wt. of CoCrMo reinforcing particles into the Ti6Al4V matrix. Sintering is studied by dilatometry tests between 1050 and 1130 °C and compact characterization is performed by SEM and XRD. Microhardness is evaluated on the polished surface in order to obtain the mechanical properties. It is found that densification is achieved by the formation of a liquid phase due to a eutectic point formed by the Ti and Co at around 1130 °C. Composites with 93% of relative density are obtained. Their microstructure is composed by the Ti6Al4V matrix surrounded by a Ti2Co phase. Average microhardness of composites is higher than that obtained for monolithic samples of both alloys. It is assessed that the control of the liquid phase is the key to obtain highly dense composites that could be used as dental or orthopedic implants.