20CrMnTiH钢唯象本构模型及动态再结晶行为  

Phenomenological constitutive model and dynamic recrystallization behavior of 20CrMnTiH steel

作　　者：龚乾江 梁益龙[1,2,3,4] 杨明[1,2,3,4] 姜云[1,2,3,4] 徐祥[1,2,3,4] 

机构地区：[1]贵州大学材料与冶金学院,贵州贵阳550025 [2]贵州省材料结构与强度重点实验室,贵州贵阳550025 [3]贵州省高性能金属结构材料与制造技术工程实验室,贵州贵阳550025 [4]高性能金属结构材料与制造技术国家地方联合工程实验室,贵州贵阳550025

出　　处：《钢铁》2017年第6期67-75,共9页Iron and Steel

基　　金：国家自然科学基金资助项目(51461006);贵州省基础应用重大应用研究资助项目(黔科合JZ字2014-2003)

摘　　要：采用Gleeble-3800热模拟试验机对20CrMnTiH钢进行了等温热压缩试验,研究了该钢在变形温度为850~1 150℃、应变速率为0.01~10 s^(-1)条件下的高温热变形行为,运用数学回归方法和热力学不可逆原理,建立了20CrMnTiH钢应变补偿的唯象本构方程和动态再结晶模型,并对该应变补偿的唯象本构模型进行了有效验证。在真应力-真应变曲线中,变形温度和应变速率对20CrMnTiH钢的流变应力影响显著,表现出正的应变速率敏感性和负的温度敏感性;由本构模型计算得到的流变应力值与试验值两者之间有很好的相关性(R=0.976 64),平均相对误差为5.544 2%;在应变硬化速率与流变应力关系曲线中,利用单一参数法和求解拐点法获得了不同变形条件下动态再结晶的临界应力σ_c和临界应变ε_c值,建立了临界应力、临界应变和Zener-Hollomon参数的数学模型ε≥ε_c=0.007 9 lnZ-0.153 23,且临界应变ε_c随着温度补偿应变速率因子Z的增加而增加。The high temperature hot deformation behavior of 20 CrMnTiH steel at deformation temperature in the range of 850-1 150 ℃ and strain rate in the range of 0.01-10 s-（-1）was discussed by isothermal compression test on Gleeble-3800 thermal simulation test machine. The phenomenological constitutive equation and dynamic recrystallization model of20 CrMnTiH steel were established by mathematical regression method and thermodynamic irreversible principle,and the constitutive model compensated by strain was verified effectively. The true stress-strain curve showed that the deformation temperature and strain rate had significant effects on the deformation temperature and strain rate on 20 CrMnTiH steel and exhibited positive strain rate sensitivity and negative temperature sensitivity. There was a good correlation（R=0.976 64） between the calculated flow stress values and the experimental values,and the average relative error was5.544 2%. In the hardening rate and flow stress curves,the critical stress σcand the critical strain εcvalue of dynamic recrystallization under different deformation conditions by single parameter method and solving the inflection point method have been obtained,and the critical stress and critical strain and Zener-Hollomon parameters of the mathematical model（ε ≥ εc=0.007 9ln Z-0.153 23） were established,and the critical strain εcincreased with the increase of temperature compensated strain rate factors Z.

关 键 词：20CRMNTIH钢 热力学不可逆原理 唯象本构方程 动态再结晶 

分 类 号：TG142.1[一般工业技术—材料科学与工程]