粉末冶金Ti-14Mo-2.1Ta-0.9Nb-7Zr合金热变形行为  

Hot Deformation Behavior of Powder Metallurgy Ti-14Mo-2.1Ta-0.9Nb-7Zr Alloy

作　　者：马琳[1] 李伟[1] 白娇娇[1] 赵丰停 MA Lin;LI Wei;BAI Jiao-jiao;ZHAO Feng-ting(College of Materials and Metallurgy,Guizhou University,Guiyang 550025,China)

机构地区：[1]贵州大学材料与冶金学院,贵阳550025

出　　处：《材料工程》2018年第10期47-54,共8页Journal of Materials Engineering

基　　金：贵州省科学技术基金项目(黔科合J字[2013]2102号);贵州大学研究生创新基金资助项目(研理工2016022号)

摘　　要：在Gleeble-1500D热模拟机上对粉末冶金制备的新型医用Ti-14Mo-2.1Ta-0.9Nb-7Zr合金进行等温热压缩实验,研究该合金在温度为780~960℃,应变速率为0.001~1s-1,变形为60%的条件下的高温变形及动态再结晶行为。采用包含变形激活能Q和温度T的双曲正弦形式修正的Arrhenius关系来描述该合金高温压缩变形时的最大变形抗力方程;并引入参数α(ε),n(ε),Q(ε)和A(ε)得到包含σ,ε·,T,ε的本构方程。结果表明:由本构方程计算得到的应力值和实验值有较好相关性(R=0.99430),平均相对误差为5.327%;最后采用加工硬化率法通过对θ-σ和lnθ-ε曲线进行三次多项式拟求解拐点的方法,得到了不同变形条件下发生动态再结晶的临界应力和临界应变值,建立了临界应力和Z参数的关系,获得动态再结晶的临界应力方程,而临界应变εc主要集中在0.01~0.04,不同变形条件下该合金发生动态再结晶的临界应变变化极小。The new medical Ti-14Mo-2.1Ta-0.9Nb-7Zr alloy was prepared by powder metallurgy.The high temperature compression behavior and the dynamic recrystallization behavior of the alloy were investigated by hot compression tests.The tests were performed with a Gleeble-1500D simulator at 780-960℃and stain rate of 0.001-1s-1 up to a deformation of 60%.The hyperbolic sine modified Arrhenius model,which included deformation activation energy Q and temperature T,was used to describe the hot compression deformation equation of maximum deformation resistance;and the material parameter function ofα(ε),n(ε),Q(ε)and A(ε),was introduced to obtain the constitutive equations.The results show that the flow stress values predicted by the proposed model have a good agreement with experimental results,high value of correlation coefficient(R=0.99430)and low value of average absolute relative error(5.327%);the critical stress and critical stain for dynamic recrystallization(DRX)under different deformation conditions are accurately calculated based on the method of work hardening rate and the inflection points,which are determined by fitting a third order polynomial to theθ-σand lnθ-εcurves.Then the mathematical models of critical stress versus Z parameter and the critical stress equations of dynamic recrystallization are deduced,the critical strainεc mainly concentrates in the 0.01-0.04 and the critical strains of dynamic recrystallization alloy under different deformation conditions change in tiny.

关 键 词：粉末冶金 Ti-14Mo-2.1Ta-0.9Nb-7Zr合金 热压缩 本构方程 动态再结晶 

分 类 号：TG146.23[一般工业技术—材料科学与工程]