Tensile properties and surface reaction layer of biomaterial, Ti-29Nb-13Ta-4.6Zr, cast by dental precision casting process using various investment materials

Ti-29Nb-13Ta-4.6Zr for biomedical applications and conventional alpha+beta type titanium Ti-6Al-4V ELI for biomedical and dental applications are subjected to dental precision casting using commercial alumina based and magnesia based investment materials, and modified magnesia based investment material. Mechanical properties and surface reaction layers of cast Ti-29Nb-13Ta-4.6Zr were investigated in order to find the suitable investment material for dental precision casting of Ti-29Nb-13Ta-4.6Zr in comparison with Ti-6Al-4V ELI. The following results were obtained. Elongation of Ti-29Nb-13Ta-4.6Zr cast into commercial alumina based investment material is lower than those cast into commercial magnesia and modified magnesia based investment materials although no big difference in strength is obtained regardless of the investment materials. The formation of surface reaction layer composed of oxide and a-case is restrained by magnesia and modified magnesia based investment materials as compared with alumina based one. The modified magnesia based investment material is better for casting of Ti-29Nb-13Ta-4.6Zr as compared with magnesia and alumina based investment materials.