基于Z参数金属热变形分段流变应力模型研究  

Investigation on Segmented Model of Flow Stress During Hot Deformation of Metal Based on Z Parameter

作　　者：王健[1,2] 王小巩[1,2] 肖宏[1,2] 

机构地区：[1]燕山大学国家冷轧板带装备及工艺工程技术研究中心,河北秦皇岛066004 [2]燕山大学亚稳材料制备技术与科学国家重点实验室,河北秦皇岛066004

出　　处：《钢铁研究学报》2013年第7期27-32,共6页Journal of Iron and Steel Research

基　　金：国家自然科学基金资助项目(51075353);国家工程中心开放性课题资助项目(NECSR-201209)

摘　　要：考虑峰值应力后的稳态应力的软化机制,构建了包括动态回复和动态再结晶过程的基于Z参数的金属热成形分段流变应力数学模型,在Gleeble-3500热力模拟试验机上采用圆柱试样对金属材料进行了进行恒温和恒速热压缩变形试验,研究其在高温塑性变形过程中流变应力的变化规律,确定其形变表观激活能Q和应变硬化指数n,得到了峰值应力,峰值应变,稳态应力与lnZ的线性关系以及动态回复参数和动态再结晶动力学的数学模型,分段流变应力模型的模拟结果与试验结果吻合较好。Considering the softening mechanism of steady state stress after peak stress, segmented model of flow stress for metal hot forming including dynamic recovery and dynamic recrystallization process was established based on Z parameter. The flow stress behaviors of cylindrical samples were investigated in the temperature range of 950-1 100℃ and strain rate of 0.01-0. 5 s^-1 on Gleeble-3500 thermo-simulation machine. The strain hardening exponent and deformation activation energy were evaluated by linear regression analysis. The peak stress/ strain and steady stress were all in linear ralationship with lnZ. In addition, dynamic recovery parameter and dynamie reerystalliazation kinetics were formulated. The flow stress constitutive equation of steel during hot compression was obtained taking the dynamic recovery and dynamic recrystalliazation into account. The results show that the dynamic recover and dynamic reerystallization occur obviously during hot compression of the test steel. The flow stress of test steel predicted by the proposed models well agrees with experimental results.

关 键 词：热压缩 流变应力 动态再结晶 峰值应变 Z参数 

分 类 号：TG115.5[金属学及工艺—物理冶金]