(1. 湘潭大学 机械工程学院，湘潭 411105；
2. 湘潭大学 焊接机器人及应用技术湖南省重点实验室，湘潭 411105；
3. 中南大学 材料科学与工程学院，长沙 410083)
摘 要: 利用XRD、TEM、显微硬度、拉伸试验等分析方法研究双级时效热处理对Ti-25Nb-10Ta-1Zr-0.2Fe医用钛合金的显微组织和力学性能的影响。结果表明：双级时效硬度曲线在单级时效的上方并且出现明显的双峰特征。双级时效后，合金的晶内形成由片层α组成的“阶梯状” α组织，对硬度产生较大的贡献。单级时效(550 ℃)与双级时效((400 ℃，1 h)+550 ℃)的相析出序列分别为β→β+α″→β+α和β→β+ω→β+α″→β+α。合金性能最优的时效工艺为(400 ℃，1 h)+(550 ℃，2 h)。在此条件下合金弹性模量、抗拉强度、伸长率分别为65 GPa、845 MPa、14.3%，具有良好的综合性能。
关键字: TNTZF合金；双级时效；显微组织；力学性能
（1. School of Mechanical Engineering, Xiangtan University, Xiangtan 411105, China;
2. Key Laboratory of Welding Robot and Application Technology of Hunan Province,
Xiangtan University, Xiangtan 411105, China;
3. School of Materials Science and Engineering, Central South University, Changsha 410083, China）
Abstract:The effects duplex aging on the microstructure and mechanical properties of Ti-25Nb-10Ta-1Zr-0.2Fe titanium alloy were studied by XRD、TEM、microhardness and tensile test analysis methods. The results indicate that the hardness curve of duplex aging is on the tops of the curve of single aging, and shows the double-peak feature. Ladder-shaped α composed of lath α in the matrix is observed after duplex aging which leads to the increase of hardness. The precipitation sequence during single (550 ℃) and duplex ((400 ℃, 1 h)+550 ℃) is determined as: β→β+α″→β+α and β→β+ω→β+α″→β+α, respectively. The optimum aging process is ((400 ℃, 1 h)+(550 ℃, 2 h)), in this condition, the elastic modulus, tensile strength and elongation of the alloy are 65 GPa、845 MPa and 14.3%, respectively, the alloy has excellent comprehensive performance.
Key words: TNTZF alloy; duplex aging; microstructure; mechanical property
