Influence of Sintering Temperature on Mechanical Properties of Ti-Nb-Zr-Fe Alloys Prepared by Spark Plasma Sintering

Ti-15Nb-25Zr-(0, 4, 8)Fe (mol.%) alloys were prepared via spark plasma sintering (SPS) for 10 min at 800, 1000, and 1200 degrees C to study the effect of sintering temperatures and Fe content on the mechanical properties of alloys. The main phase of the alloys sintered at 800 degrees C is alpha phase. When the temperature is increased to 1000 and 1200 degrees C, the alloys are mainly beta phase. Raising the sintering temperature can promote the diffusion of elements. Therefore, high strength and high plasticity are obtained in the alloys sintered at high temperature. The compressive strength of Ti-15Nb-25Zr sintered at 1200 degrees C is 1604 MPa, and the fracture strain is around 35%. The strength and plasticity are influenced by the complex effects of elemental diffusion, grain boundary and solid-solution strengthening. Adding Fe can improve the diffusion of elements, promote the formation of beta grains and supply solid-solution strengthening effect. As the sintering temperature is increased, the compressive strength of Ti-15Nb-25Zr-4Fe shows an increasing trend and the plasticity is almost not changed. The Fe content is excessive in Ti-15Nb-25Zr-8Fe, which leads to some disadvantages including intermetallic compounds formation and grain boundary coarsening. The mechanical properties of Ti-15Nb-25Zr-8Fe are not always better than those of Ti-15Nb-25Zr-4Fe. The compressive strength of Ti-15Nb-25Zr-8Fe shows an increasing trend and the plasticity firstly increases and then decreases when the temperature is raised from 800 up to 1200 degrees C. Although the sintering time of SPS is short, Ti-15Nb-25Zr-(4, 8)Fe sintered at 1000 degrees C and Ti-15Nb-25Zr-(0, 4)Fe sintered at 1200 degrees C show good combination of strength and plasticity.