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.

采用传统粉末冶金结合半固态烧结工艺，制备了CoCrMo颗粒增强Ti6Al4V复合材料。将20%质量分数的CoCrMo增强颗粒混入Ti6Al4V基体中，制备得到目标复合材料。通过热膨胀测试在1050至1130℃范围内对烧结过程展开研究，并采用扫描电子显微镜（SEM）与X射线衍射（XRD）对压坯进行表征。对抛光表面开展显微硬度测试，以获取材料的力学性能数据。研究发现，在约1130℃时，钛与钴形成共晶点，通过液相生成实现了材料致密化。最终获得相对密度达93%的复合材料，其微观组织由Ti6Al4V基体与环绕其的Ti2Co相构成。该复合材料的平均显微硬度高于两种合金的单体试样。经评估可知，液相调控是制备高致密复合材料的核心关键，此类复合材料可应用于牙科或骨科植入领域。