Two-stage sintering investigation of Ti-Zr-Nb biomedical alloys

    Machines. Technologies. Materials., Vol. 13 (2019), Issue 9, pg(s) 404-407

    Biomedical alloys 19Ti-59Zr-22Nb and 40 Ti-35Zr-25Nb were produced by blended elemental powder metallurgy approach using TiH2, ZrH2 and Nb powders. Usage of hydrogen as temporary alloying element for titanium and zirconium leads to activated sintering and decreased residual porosity of the alloys produced. Contrary, large amount of Nb powder negatively affects sintering and 6-9% residual porosity is observed in sintered alloys. Two-stage sintering (TSS) approach which includes preliminary sintering of powder blends, hydrogenation of sintered products, crushed in powder and sintering again, was used to obtain uniform alloys with reduced porosity. Volume changes of sintering of noted powder blends and prealloyed powders were investigated together with microstructure of sintered materials. Using prealloyed hydrogenated powders in TSS process resulted in activated densification, improved homogeneity of alloy microstructures and low (~2%) residual porosity.