应用热加工图研究TC17合金片状组织球化规律

Study on Globularization of Lamellar α Structure in TC17 Titanium Alloy during Hot Deformation Using Processing Map

采用加工图理论分析了TC17（Ti-5Al-4Mo-4Cr-2Sn-2Zr）钛合金在高温变形过程中的片状α球化规律。结果表明：用加工图理论分析材料的高温变形行为能准确直观地反映出材料在不同变形条件下的组织演变规律。分析加工图发现：TC17合金在840℃～870℃，应变速率0．5s^-1～3s^-1之间变形是片状α组织球化的理想区域，此时对应的能量耗散效率值为45％左右；在850℃～910℃，较高应变速率（〉5s^-1）下对TC17合金加工易发生流变不稳定现象，形成绝热剪切带。

The globularization of lamellar α microstructure in Ti-5Al-4Mo-4Cr-2Sn-2Zr （TC 17） alloy was studied using processing map theory. The deformation behavior at elevated temperature and the microstructure evolution under different deformation condition can be indicated exactly and directly by the processing map. As a result, the deformation at 840℃-870℃ and strain rate of 0.5 s^-1-3 s^-1 is the optimum globularization condition of lamellar α for TC17 alloy, and the corresponding efficiency of power-dissipation is about 45%, TC 17 alloy exhibits flow instability regimes due to adiabatic shear bands formation at higher strain rates（〉5 s^-1）.