核电装备用奥氏体不锈钢的高温本构模型及动态再结晶  

Constitutive Equation and Dynamic Recrystallization Behavior of 316L Austenitic Stainless Steel for Nuclear Power Equipment

作　　者：程晓农[1] 桂香 罗锐[1] 杨雨童 陈乐利 王威[1] 王稳 CHENG Xiaonong;GUI Xiang;LUO Rui;YANG Yutong;CHEN Leli;WANG Wei;WANG Wen(School of Materials Science and Engineering,Jiangsu University,Zhenjiang 212013)

机构地区：[1]江苏大学材料科学与工程学院

出　　处：《材料导报》2019年第11期1775-1781,共7页Materials Reports

基　　金：“十二五”国家高技术研究发展计划(863计划)重大项目(2012AA03A501)~~

摘　　要：采用热模拟压缩实验研究核电装备用316L奥氏体不锈钢在变形温度为900~1100℃、应变速率为0.01~5s^-1时的高温变形行为。根据压缩实验数据绘制流变应力曲线;基于Arrhenius关系并考虑应变量因素,建立耦合应变量因素的改进型本构方程;结合光学显微镜(OM)观察材料变形过程中微观组织的特征;根据加工硬化率-流动应力曲线确定316L不锈钢的动态再结晶临界应变并基于Avrami方程建立其动态再结晶体积分数模型。结果表明:在316L不锈钢热变形过程中,较低的温度和较快的应变速率对应的流变应力也较大;耦合应变量因素的本构模型预测316L不锈钢的流变应力,预测值与实验值的相关系数为0.98688,平均相对误差仅4.6%,该模型能较好地预测316L不锈钢在热变形过程中的变形抗力。316L不锈钢易在高温、低速的加工条件下发生动态再结晶行为,其动态再结晶体积分数与应变呈S形变化。该模型所得的预测值与实验数据之间的相关性较好,能很好地预测316L不锈钢在热加工过程中发生动态再结晶的体积分数。The hot deformation behavior of 316L austenitic stainless steel used in nuclear power equipment was studied by hot compression tests in the temperature range of 900-1 100 ℃, and in the strain rate range of 0.01-5 s^-1 . According to the data of hot compressive experiment, the flow stress curves of 316L under different deformation conditions were plotted. The constitutive model considering the compensation of strain for predicting the flow stress of 316L under all test conditions was developed on the basis of Arrhenius-type equation. The microstructural evolution of 316L during deformation was observed via an optical microscope. The critical strain of dynamic recrystallization of 316L stainless steel is identified based on the work hardening rate versus flow stress curves. The DRX kinetics for 316L can be represented in the form of Avrami equation. The results show that either decreasing deformation temperature or increasing strain rate makes the flow stress level reduce remarkably. The accuracy of the developed model was evaluated using standard statistical parameters such as correlation coefficient and average absolute relative error. It suggested that this developed constitutive equation could accurately predict high temperature flow behaviors of 316L.It is found that the DRX mainly occurred at high strain rates and high temperatures. The DRX volume fraction increased towards 1.0 with an increase in strain in terms of the S-shape and the predicted volume fraction of new grains based on the developed model agrees well with the experimental results.

关 键 词：316L不锈钢 应力-应变曲线 热变形 动态再结晶 

分 类 号：TG142.71[一般工业技术—材料科学与工程]