粉末冶金TiAl合金的热变形行为研究  

Hot Deformation Behavior of Powder Metallurgical TiAl Alloy

作　　者：刘娜[1] 李周[1] 袁华[1] 许文勇[1] 张勇[1] 张国庆[1] 

机构地区：[1]北京航空材料研究院先进高温结构材料国防科技重点实验室,北京100095

出　　处：《航空材料学报》2013年第5期1-5,共5页Journal of Aeronautical Materials

基　　金：国家高科技研究发展计划863项目(2013AA031103)

摘　　要：在Gleeble-3500热模拟试验机上对粉末冶金TiAl合金进行热压缩试验,变形温度为1050 ～ 1200℃,,应变率0.001 ～0.1 s-1,工程应变量为50％,研究其在高温压缩变形中的流变应力行为.研究结果表明：在实验范围内,粉末冶金TiAl合金在热压缩变形过程中发生了明显的动态再结晶,其流变应力随应变速率的增大而增大,随变形温度的升高而降低;粉末冶金TiAl合金热压缩变形过程的流变行为可用包含Arrhenius项的Zener-Hollomon参数来描述,所获得的峰值应力表达式为：σ=90.91 In{（Z/1.68×1016）1/2.06＋[（Z/1.68×1016）2/2.06＋1]1/2},其变形激活能为477.56k J/mol,经验算该方程可以较好地描述该合金的变形特点.Hot deformation behavior of powder metallurgical TiAl alloy was investigated on Gleeble-3500 thermal mechanical simulator at a temperature range of 1050-1200℃,and a strain rates range of 0.001-0.1s-1 with engineering strain of 50％.The results show that,the flow stress of PM TiAl alloy is sensitive to both deformation temperature and strain rate,significantly decreasing with the increase of deformation temperature and the decrease of strain rate.Dynamic recrystalization occurs during the hot compression.The flow stress model of TiAl alloy during hot compression was established based on the Arrhenius equations and Zener-Hollomom parameter,the regressed expression is σ =90.91 In { （Z/1.68 × 1016）1/2.06 ＋ [（Z/1.68 × 1016）2/2.06 ＋ 1] 1/2}.The hot deformation activation energy of PM TiAl alloy was calculated about 477.56kJ/mol.And the flow stress constitutive model can efficiently predict the deformation behavior of the PM TiAl alloy during high temperature deformation.

关 键 词：粉末冶金TiAl合金 热变形 变形激活能 本构模型 

分 类 号：TG146.2[一般工业技术—材料科学与工程]