(1. 湘潭大學(xué) 機(jī)械工程學(xué)院，湘潭 411105；
2. 湘潭大學(xué) 焊接機(jī)器人及應(yīng)用技術(shù)湖南省重點實驗室，湘潭 411105；
3. 中南大學(xué) 材料科學(xué)與工程學(xué)院，長沙 410083)
摘 要: 利用XRD、TEM、顯微硬度、拉伸試驗等分析方法研究雙級時效熱處理對Ti-25Nb-10Ta-1Zr-0.2Fe醫(yī)用鈦合金的顯微組織和力學(xué)性能的影響。結(jié)果表明：雙級時效硬度曲線在單級時效的上方并且出現(xiàn)明顯的雙峰特征。雙級時效后，合金的晶內(nèi)形成由片層α組成的“階梯狀” α組織，對硬度產(chǎn)生較大的貢獻(xiàn)。單級時效(550 ℃)與雙級時效((400 ℃，1 h)+550 ℃)的相析出序列分別為β→β+α″→β+α和β→β+ω→β+α″→β+α。合金性能最優(yōu)的時效工藝為(400 ℃，1 h)+(550 ℃，2 h)。在此條件下合金彈性模量、抗拉強(qiáng)度、伸長率分別為65 GPa、845 MPa、14.3%，具有良好的綜合性能。
關(guān)鍵字: TNTZF合金；雙級時效；顯微組織；力學(xué)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
