Fabrication of Porous Ti25TaxB Alloy by Powder Metallurgy

Ti25Ta alloy has shown to have the best combination of properties for biomedical applications in comparison to the widely used Ti6Al4V alloy. However, the main disadvantage is its poor wear resistance, thus, to overcome this disadvantage the addition of boron is studied in this work. To reach our objective, Ti25TaxB alloys were obtained by mechanical milling. Three different quantities of B were added 2, 4 and 6 at %. Powders were milled during 24 h under dry conditions. Then, milled powders were uniaxial pressed at 400 MPa. Green compacts were sintered at 1260°C during 1 h under argon atmosphere. Microstructure was observed by SEM and X-ray diffraction. Results shows that addition of boron improves the compaction behavior. On the contrary, during sintering, addition of boron reduces the densification because of the in-situ TiB formation. Sintered compacts have around 20 vol % of pores. The microstructure of sintered compacts is composed of three different phases; β-Ti, α'-Ti and TiB. The microhardness of the sample with 2 at % of boron is improved 50% with respect to the one measured for the Ti25Ta alloy. It is concluded that conventional sintering allows obtaining porous compacts with high hardness that could be used for biomedical applications.