Effects of Heat Treatment on Mechanical Properties and Microstructure Evolutions of Ti-5321 Alloy

^a State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an, China
^b College of Materials Science and Engineering and Tech Institute for Advanced Materials, Nanjing Tech University, Nanjing, China
^c Northwest Institute for Non-ferrous Metal Research, Xi’an, China

^* jingzhe.niu@stu.xjtu.edu.cn / njzhe91@gmail.com, *guoyanhua@njtech.edu.cn

Abstract

This work presents a comprehensive study on the microstructure evolution and mechanical property under different heat treatment procedures of a new near β type titanium Ti-5321(Ti-5Al-3Mo-3V-2Cr-2Zr-1Nb-1Fe). Two solution temperatures(830°C and 900°C) and a group of aging temperatures(300-650°C) were carried out to investigate the influence of heat treatment on this new alloy. The strengthening mechanism of Ti-5321 after solution and aging treatment was discussed by analyzing the microstructure and its mechanical properties. The best ultimate tensile strength can be achieved to 1564 MPa with 5% on elongation when solution treated at 830°C and aging at 450°C for this new alloy. The lamellar and globular α grains can be found in all 830°C solution treated specimens which contribute to a better ductility. Ultra-fine α phase can be found in all low aging temperature treated specimens but will coarsen significantly when raising the aging temperature and thus increase the tensile strength and lower the ductility. All these results can provide a comprehensive guidance on heat treatment for this new near β type titanium in the future.