(1. 北京有色金属研究总院 加工工程研究中心，北京 100088；
2. 上海交通大学 金属基复合材料国家重点实验室, 上海 200030)
摘 要: 在Gleeble−1500D热模拟机上采用等温压缩实验，研究原位合成TiB2/6351复合材料在变形温度为300~ 550 ℃和应变速率为10−3~10 /s条件下的流变变形行为。结果表明：在实验范围内，该复合材料高温压缩时均存在稳态流变特征且属于正应变速率敏感材料；在低应变速率和较高温度条件下, 随变形程度的增加，流变应力增加到峰值后缓慢下降，逐渐趋于平稳，呈现明显的动态再结晶特征；而在较高应变速率和较低温度下，呈现明显动态回复特征；可用包含Arrhenius项的Zener-Hollomon参数描述TiB2/6351复合材料高温压缩流变行为。通过线性回归分析和优化计算，得出流变应力σ解析表达式中A、α和n分别为3.52×1010 /s、0.023 MPa−1和7.33，其热变形激活能Q为170.10 kJ/mol。
关键字: 原位TiB2/6351复合材料；热压缩变形；流变应力；Zenner-Hollomon参数；热变形激活能
（1. Processing Engineering Research Center, General Research Institute for Nonferrous Metals, Beijing 100088, China;
2. State Key Laboratory of Metal Matrix Composite, Shanghai Jiao Tong University, Shanghai 200030, China）
Abstract:The flow stress features of in-situ TiB2/6351 composites were studied by isothermal compression at 300− 550 ℃ and strain rate of 10−3−10 /s on Gleeble−1500D system. The results show that TiB2/6351 composites have the steady-state flow characteristics and belong to positive strain rate sensitized materials during hot compression deformation. At lower strain rates and higher temperatures，with the increase of strain， the flow stress increases to peak value and then falls down, at last tends to smooth gradually. The curves express the feature of dynamic recrystallization. But at higher strain rates and lower temperatures, dynamic recovery occurs obviously. The flow stress of in-situ TiB2/6351 composites during high temperature compression deformation can be represented by Zener-Hollomon parameter including Arrhenius term. A, α and n in the analytical expressions of flow stress are 3.52×1010 /s, 0.023 MPa−1 and 7.33, respectively, by linear regression analysis and optimization calculation. The hot deformation activation energy of TiB2/6351 composites during hot deformation is 170.10 kJ/mol.
Key words: in-situ TiB2/6351 composite; hot compression deformation; flow stress; Zener-Hollomon parameter; deformation activation energy
