Ti_(2)AlNb合金应变速率敏感指数和应变硬化指数与变形参数和晶粒尺寸关系研究  

Research on the Relationship Between the Strain Rate Sensitivity Exponent, Strain Hardening Exponent and Deformation Parameters, Grain Size of Ti_(2)AlNb Titanium Alloy

作　　者：朱艳春[1] 邵珠彩 罗媛媛[2] 黄志权[1] 牛勇 秦建平[1] ZHU Yanchun;SHAO Zhucai;LUO Yuanyuan;HUANG Zhiquan;NIU Yong;QIN Jianping(School of Mechanical Engineering,Taiyuan University of Science and Technology,Taiyuan 030024,China;Northwest Institute for Nonferrous Metal Research,Xi’an 710016,China)

机构地区：[1]太原科技大学机械工程学院,太原030024 [2]西北有色金属研究院,西安710016

出　　处：《材料导报》2023年第5期152-157,共6页Materials Reports

基　　金：山西省基础研究计划项目(202203021211208);陕西省重点研发计划一般项目(2020GY-284);国家自然科学基金(52075357);太原科技大学预研项目(20198011)。

摘　　要：以Ti_(2)AlNb合金板材为研究对象,基于变形温度为1 273~1 423 K、应变速率为0.001~10 s^(-1)范围内的等温恒应变速率热压缩实验,深入分析了变形参数和微观组织对应变速率敏感指数m和应变硬化指数n的影响。结果表明:Ti_(2)AlNb合金的流动应力随变形温度的升高和应变速率的降低而减小;Ti_(2)AlNb合金等温压缩过程中的峰值m为0.61,出现在1 323 K/0.001 s^(-1);当变形温度为1 273~1 323 K时,m随应变速率的增大而减小,当变形温度为1 373~1 423 K时,m随应变速率的增大而增大;当应变速率为0.001 s^(-1)时,n随应变的增大呈现先减小后增大的趋势,而当应变速率为0.01~10 s^(-1)时,n却呈现先增大后减小的变化趋势;Ti_(2)AlNb合金应变硬化指数n值和应变速率敏感指数m值均随着晶粒尺寸的增大而减小;Ti_(2)AlNb合金板材较优的加工区间为1 273~1 323 K/0.001~0.01 s^(-1)以及1 373~1 423 K/0.1~1 s^(-1)。这对通过工艺优化组织,进而改进Ti_(2)AlNb合金板材的性能具有重要的理论意义和工程价值。The effects of deformation parameters and microstructure on the strain rate sensitivity m and strain hardening exponent n were analyzed in depth based on isothermal compression experiments of Ti_(2)AlNb alloy plates at the deformation temperatures of 1 273—1 423 K and the strain rates in the range of 0.001—10 s^(-1). The results showed that the flow stress of Ti_(2)AlNb alloy decreases with the increasing deformation temperature and decreasing strain rate. The maximum m value of 0.61 occurred at 1 323 K and a strain rate of 0.001 s^(-1) during the isothermal compression of Ti_(2)AlNb alloy. Moreover, the m value decreased with the increase of strain rate in the deformation temperature range of 1 273—1 323 K. On the contrary, the m value increased with the increase of strain rate in the deformation temperature range of 1 373—1 423 K. Furthermore, the n value decreased firstly and then increased with the increase of strain at the strain rate of 0.001 s^(-1), but at the strain rate of 0.01—10 s^(-1), the n value increased firstly and then decreased with the increase of strain. In addition. the strain hardening exponent and strain rate sensitivity of Ti_(2)AlNb alloy both decreased with the increase of grain size. Finally, the better processing windows of Ti_(2)AlNb alloy sheet were given as 1 273—1 323 K/0.001—0.01 s^(-1)and 1 373—1 423 K/0.1—1 s^(-1). This has important theoretical significance and engineering value for to improve the properties of Ti_(2)AlNb alloy sheet by optimizing the microstructure through the process.

关 键 词：Ti_(2)AlNb合金 应变速率敏感指数 应变硬化指数 组织演变 

分 类 号：TG146.23[一般工业技术—材料科学与工程]