万志鹏,孙宇,胡连喜,于欢.TiAl基合金动态再结晶临界模型建立[J].稀有金属材料与工程,2018,47(3):835~839.[Wan Zhi-peng,Sun Yu,Hu Lian-xi,Yu Huan.Modeling of the critical conditions on dynamic recrystallization for TiAl-based alloy[J].Rare Metal Materials and Engineering,2018,47(3):835~839.]
TiAl基合金动态再结晶临界模型建立
投稿时间:2016-01-25  修订日期:2016-03-14
中文关键词:  Ti-47Al-2Nb-2Cr合金  动态再结晶  临界应变  Z参数
基金项目:国家自然科学基金(51405110),中国博士后科学基金(2014M551234),高等学校博士学科点专项科研基金(20132302120002),黑龙江省博士后基金(LBH-Z14096)。
中文摘要:
      依据粉末冶金Ti-47Al-2Nb-2Cr合金热模拟压缩实验结果,研究了变形温度为950-1150oC、应变速率为0.001-0.1s-1条件下材料的流变力学行为。采用Poliak和Jonas所提出的临界条件动力学理论,确定了动态再结晶临界应变(εc)和临界应力(σc),揭示了变形温度与应变速率对εc和σc的影响规律。结果表明,温度补偿应变速率因子Z与εc、σc、εp(峰值应变)和σp(峰值应力)间的关系可以采用指数函数形式描述。建立了该合金动态再结晶临界发生模型:εc=1.2×10-3Z0.147,动态再结晶临界应变与流变应力曲线峰值应变的比值约为0.73。根据对模型的分析表明,临界应变与Z参数之间呈现正相关性,随着Z参数的减小(变形温度升高或应变速率降低),材料发生动态再结晶的临界应变减小,说明随着变形温度的升高与应变速率的下降,能够促进动态再结晶行为的发生,并通过对热变形后微观组织的观察,验证了所建立动态再结晶临界模型的可靠性。
Modeling of the critical conditions on dynamic recrystallization for TiAl-based alloy
英文关键词:Ti-47Al-2Nb-2Cr alloy  dynamic recrystallization  critical strain  Z parameter.
英文摘要:
      The flow stress behavior of powder metallurgy (PM) Ti-47Al-2Nb-2Cr alloy during hot deformation was investigated at temperature of 950-1150oC and strain rates of 0.001-0.1s-1. In this paper, the influence of deformation parameters on the critical conditions of the dynamic recrystallization behavior was studied systematically. Based on the analysis of flow stress curves under different hot processing parameters, the critical strain (εc) and critical stress (σc) were obtained with the help of the critical condition theory proposed by Poliak and Jonas. It is also shown that the critical condition model was established by employing the strain rate and temperature compensation factor (Z): εc=1.2×10-3Z0.147. The occurrence of dynamic recrystallization behavior will be promoted with the increase of deformation temperature and the decrease of strain rate. Moreover, the reliability of the established model was verified by the observation of deformed microstructure.
作者单位E-mail
万志鹏 哈尔滨工业大学 金属精密热加工国家级重点实验室 waynedapeng@163.com 
孙宇 哈尔滨工业大学 金属精密热加工国家级重点实验室  
胡连喜 哈尔滨工业大学 金属精密热加工国家级重点实验室 hulx@hit.edu.cn 
于欢 哈尔滨工业大学 金属精密热加工国家级重点实验室  
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