| Alumina ceramic is a very important inert bio-ceramic material, which possesses high hardness, high melting point, good chemical stability, good mechanical properties and wear-resisting property. Its limitation is brittleness. Ti is a kind of widely used biomaterial for its excellent biocompatibility, firm combination with biological interface, similar elastic modulus to bone, low density, good corrosion resistance as well as good ductility. Its main drawback in bio-application is poor wear resistance. In the present work, fabrication and properties of Al2O3/Ti network composites were investigated. The composites are expected to have improved the strength and toughness, good wear resistance and chemical stability, as well as good biocompatibility, which can be potentially used in bio-applications.Firstly, the effect of Ti and TiH2 as the titanium source on properties of the Al2O3/Ti network composites was studied. Then, the strengthening and toughening of the composite by the addition of Fe and TiCN was investigated. The Al2O3/Ti, Al2O3/Ti-Fe and Al2O3/Ti-TiCN composites were fabricated by the hot-pressing method, and mechanical properties and cell toxicity of the composites were tested.The results show that Ti particles have a continuous network distribution in the Al2O3/20vol%Ti composites. The composite with Ti powder as the Ti source has better mechanical properties than that with TiH2 as the Ti source. The three point bending strength, fracture toughness and bending elastic modulus of the composite are 182 MPa,4.1 MPa·m1/2 and 62.9 GPa, respectively, meeting the requirement of properties of biomaterials.The network structure is more continuous in the Al2O3/Ti-Fe composites. The solution phase of Fe and Ti distributes homogenously in the alumina matrix, improving mechanical properties of the composites. Relative density and hardness of the composite is 99.8% and 14.5GPa, respectively when 2.5vol% of Fe was added. Compared with the Al2O3/20vol%Ti composites, the bending strength (215 MPa) and fracture toughness (5.6 MPa-m1/2) increases by 18% and 37%, respectively.The Al2O3/Ti-5vol%TiCN composite has a relative density of 99.0%, Vickers hardness of 15.9 GPa and bending elastic modulus of 47.4 GPa. Compared with the Al2O3/20vol%Ti composites, the bend strength (190MPa) increases by 4.8%, while the fracture toughness (3.8 MPa·m1/2) decreases by 7.3%. Cytotoxic test showed that the L929 cell RGR values of the Al2O3/Ti system network bio-composites were over 80% at day 1, day 3 and day 7. The cells grew in good condition on the seventh day. The results indicate that the composites have no toxicity and are good in biocompatibility.
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