Microstructure and Mechanical Properties of Ti-25Nb-4Ta-8Sn Alloy Prepared by Spark Plasma Sintering

Abstract

As the commercially most-used Ti-6Al-4V alloy has a different modulus of elasticity compared to the modulus of elasticity of bone and contains allergenic elements, β-Ti alloy could be a suitable substitution in orthopedics. The spark plasma sintering (SPS) method is feasible for the preparation of materials, with very low porosity and fine-grained structure, leading to higher mechanical properties. In this study, we prepared quaternary Ti-25Nb-4Ta-8Sn alloy using the spark plasma sintering method. The material was also heat-treated in order to homogenize the structure and compare the microstructure and properties in as-sintered and annealed states. The SPS sample had a modulus of elasticity of about 63 ± 1 GPa, which, after annealing, increased to the value of 73 ± 1 GPa. The tensile yield strength (TYS) of the SPS sample was 730 ± 52 MPa, ultimate tensile strength (UTS) 764 ± 10 MPa, and ductility 22 ± 9%. Annealed samples reached higher values of TYS and UTS (831 ± 60 MPa and 954 ± 48 MPa), but the ductility decreased to the value of 3 ± 1%. The obtained results are discussed considering the observed microstructure of the alloy.

Keywords

• titanium alloy
• β-titanium
• Ti-25Nb-4Ta-8Sn
• spark plasma sintering
• low modulus