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Ti150 钛合金热变形行为及显微组织演变研究
Study on the Hot-deformation Behavior and Microstructure Evolution of Ti150 Alloy
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- DOI:
- 作者:
- 景春红 1，2，李江 1，3，邓浩 2，杨靖雲 2，傅强 2，彭文雅 4，李钢 4
JING Chunhong1, 2,LI Jiang1, 3,DENG Hao2,YANG Jingyun2,FU Qiang2,PENG Wenya4,LI Gang4
- 作者单位:
- 1. 西北工业大学 凝固技术全国重点实验室，陕西 西安 710072；2. 中国第二重型机械集团德阳万航模锻有限责任公司， 四川 德阳 618000；3. 西北工业大学 陕西省高性能精确成形技术与装备重点实验室，陕西西安 710072；4. 中国航发湖 南动力机械研究所，湖南 株洲 412000
1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072,China; 2. China National Erzhong Group Deyang Wanhang Die Forging Co., Ltd., Deyang 618000,China; 3. Shaanxi Key Laboratory of High-Performance Precision Forming Technology and Equipment, Northwestern Polytechnical University, Xi'an 710072, China; 4. AECC Hunan Aviation Powerplant Research Institute, Zhuzhou 412000,China
- 关键词:
- Ti150；热模拟压缩实验；本构方程；热加工图；热变形行为
Ti150; hot compression test; constitutive equation; hot processing map; hot deformation behavior
- 摘要:
- 针对 Ti150 近 α 钛合金热变形工艺，研究了变形温度 970~1 040 ℃，应变速率 10-3~1 s-1，变形量 60%的热变形行为以及组织演变规律。 分析了真应变、变形温度与应变速率等参数对流动应力的影响规律，基于应力-应变曲线数据建立了考虑应变补偿的 Arrhenius 本构方程，并构建了基于 Prasad 判据的热加工图。 结果表明，Ti150 合金在不同温度区 间 流 变 应 力 对 速 率 的 响 应 有 着 明 显 的 差 异 ，变形 温 度 越 高 ，较高 应 变 时 ，峰值 应 力 下 降 幅 度对 变 形 速 率 越 敏感 ， 且在 高 应 变 速 率 时 发生 不 连 续 屈 服 现 象 ， 计算 的 变 形 激 活 能 为 919 kJ/mol， 建立 的 考 虑 应 变 补 偿 的 Arrhenius本构 模型预测误差 AARE=6.53%， 相关系数 R=0.985 6， 模型预测精度较高； 热加工图表明最优工艺参数范围为温度970~1 010 ℃，应变速率 10-2~1 s-1。利用光镜(OM)及电子背散射衍射(EBSD)等技术手段，分析试样的微观组织特征。结果表明，应变速率对组织演变路径具有决定性作用，高应变速率时，剧烈的塑性变形导致位错快速增殖，变形储能成为驱动相变的核心因素，但由于热激活时间不足，组织重构受限；低应变速率时，充分的热激活条件促使扩散机制主导相变进程，位错通过动态回复 / 再结晶逐步释放畸变能，最终实现组织稳态化。
The hot deformation behavior and microstructure evolution of a Ti150 near-α titanium alloy were investigated at deformation temperatures ranging from 970~1 040 ℃,strain rates ranging from 10-3~1 s-1,and a deformation amount of 60%. The influences of the true strain, deformation temperature, and strain rate on the flow stress were analysed. On the basis of the stress-strain curve data, an Arrhenius constitutive equation considering strain compensation was established, and ahot working map based on the Prasad criterion and criterion was constructed. The results show that the response of the flow stress to the strain rate of the Ti150 alloy varies significantly across different temperature ranges. The higher the deformation temperature is, the more sensitive the peak stress drop is to the deformation rate at higher strains. Discontinuous yielding is observed at high strain rates. The calculated activation energy for deformation is 919 kJ·mol-1. The prediction error of the established Arrhenius constitutive model considering strain compensation is AARE=6.53%, and the correlation coefficient R is 0.985 6, indicating high prediction accuracy. The hot working map indicates that the optimal process parameter range is a temperature range of 970 to 1 010 ℃ and a strain rate of 10-2 to 1 s-1.The microstructure characteristics of the samples were analysed via optical microscopy (OM) and electron backscatter diffraction (EBSD). The results show that the strain rate plays a decisive role in the microstructure evolution path. At high strain rates, intense plastic deformation leads to rapid dislocation proliferation, and deformation energy storage becomes the core factor driving phase transformation. However, owing to insufficient thermal activation time, microstructure reconstruction is limited. At low strain rates, sufficient thermal activation conditions promote the diffusion mechanism to dominate the phase transformation process, and dislocations gradually release distortion energy through dynamic recovery/recrystallization, ultimately achieving microstructure stabilization.