基于摩擦修正的TB6合金流变应力行为研究及本构模型建立  

Flow Stress Behavior and Constitutive Model of As-Cast TB6 Titanium Alloy Based on Friction Correction

作　　者：段园培[1] 黄仲佳[1] 余小鲁[1] 邢昌[1] 孙宇峰[1] 

机构地区：[1]安徽工程大学机械与汽车工程学院、高性能有色金属材料安徽省省级重点实验室,安徽芜湖241000

出　　处：《稀有金属》2014年第2期202-209,共8页Chinese Journal of Rare Metals

基　　金：国家自然科学基金项目(50405020);安徽工程大学引进人才科研启动基金项目(2011YQQ002)资助

摘　　要：TB6合金是一种高强高韧近B钛合金。采用GIeeble-3500热模拟试验机对铸态TB6钛合金进行了等温热压缩变形试验，变形温度范围为700～900℃，应变速率范围为0．001-1．000s-1，研究了铸态TB6合金热变形流变应力行为，分析了热压缩后的金相显微组织，基于摩擦修正后的流变应力曲线采用双曲正弦形式的修正Arrhenius关系对TB6钛合金的本构模型进行回归。结果表明：铸态TB6合金的热变形行为对变形温度和应变速率较为敏感，随着变形温度的降低和应变速率的增加流变应力显著增大；其热变形机制以动态回复和动态再结晶为主；得到铸态TB6钛合金热变形本构方程，比较回归模型计算的应力值与实测值其平均相对误差仅为1．48％，因此采用Z参数的双曲正弦函数形式能够较为精确地预测铸态TB6合金高温变形时的流变应力。以上研究为TB6钛合金塑性加工过程的模拟和控制提供了理论基础。TB6 is a near 13 titanium alloy with high strength and high fracture toughness. Hot compression tests were performed on a Gleeble-3500 thermal simulation testing machine under isothermal hot working conditions of varying temperatures （between 700 and 900 ℃ ） and strain rates （ between 0.001 and 1. 000 s-1 ）. Based on the true stress-strain curves corrected for friction, flow stress be- havior and deformation mechanism were analyzed, and the constitutive model of as-cast TB6 titanium alloy was established based Arrhe- nius-type hyperbolic sine equation. The hot deformation microstructures of the test samples were observed by optical microscope（OM）. The results indicated that the hot deformation behavior of as-cast TB6 alloy was highly sensitive to temperature and strain rate, and the true stress markedly increased with temperature decreasing and strain rate increasing. Dynamic recovery and dynamic recrystallization were the predominant softening mechanisms during hot deformation of as-cast TB6 titanium alloy. The constitutive model of as-cast TB6 titanium alloy was obtained, and comparing with experimental stress and predicted stress, the average relative error was only 1.48%. The result showed that the Arrhenius-type hyperbolic sine equation with Z parameter could accurately predict the flow stress of as cast TB6 alloy during high temperature deformation. This work could provide a guideline for the simulation and control of plastic deformation of as-cast TB6 titanium alloy.

关 键 词：铸态TB6钛合金 热变形 流变应力 摩擦修正 本构方程 

分 类 号：TG146[一般工业技术—材料科学与工程]