The effect of precursory α and ωphase on microstructure evolution and tensile properties of metastable β titanium alloy

The microstructure evolution and tensile properties in a metastable beta & nbsp;titanium alloy, Ti-5Al-5Mo-5V-3Cr-0.6Fe alloy with different aging conditions were investigated. The microstructure evolution of omega & nbsp;and alpha & nbsp;phase precipitated during low-temperature aging was characterized by the dilatometer test and transmission electron microscopy. The results show that the nanoscale omega & nbsp;phase formed during low-temperature aging cannot affect the tensile properties due to its small size which fails to change the deformation mechanism or strengthen the beta & nbsp;phase. Meanwhile, the small size omega & nbsp;phase also fails to assist secondary a (alpha(s)) nucleation and refine alpha(s) during high-temperature aging due to omega & nbsp;dissolution. The alpha & nbsp;phase precipitated preferentially during low-temperature aging plays a considerable role in refining lamellar alpha(s) by occupying the space of beta & nbsp;matrix that hinder the growth of lamellar alpha(s). The a +& nbsp;beta & nbsp;solution-treatment with two-step aging successfully refines the lamellar alpha(s) which in turn increased the tensile strength with small reduction of ductility.(C) 2021 The Authors. Published by Elsevier B.V.& nbsp;

Automated summary

The microstructure evolution and tensile properties in a metastable beta titanium alloy, Ti-5Al-5Mo-5V-3Cr-0.6Fe alloy, with different aging conditions were investigated. The results showed that the nanoscale omega phase formed during low-temperature aging had no effect on the tensile properties. Additionally, the small size omega phase failed to assist secondary alpha(s) nucleation and refine alpha(s) during high-temperature aging due to omega dissolution. On the other hand, the alpha phase precipitated during low-temperature aging played a considerable role in refining lamellar alpha(s) and increasing tensile strength.