Microstructural evolution and mechanical properties of a novel biomedical Ti-6Zr-4Fe alloy during solution and aging treatment

Microstructural evolution and its effect on microhardness and Young's modulus of Ti-6Zr-4Fe alloy solution and aging treated at different temperatures were studied. The α phase transformed into β phase completely at 860 °C, meanwhile, the athermal ω phase was found at 860 °C and it resulted in a higher Young's modulus. The ω phase content increased from 250 °C to 400 °C, and the content decreased with further increase of aging temperature, there were only α phase and β phase at 600 °C. The phase transformation sequence was β → ω + β → ω + α + β → α + β during aging treatment. The microhardness increased from 315 HV to 492 HV due to the element solution strengthening and phase transformation strengthening. The peak microhardness of Ti-6Zr-4Fe alloy aged at 400 °C reached 652 HV. The formation of ω phase resulted in the increase of microhardness and Young's modulus in Ti-6Zr-4Fe alloy.