690合金高温变形行为与动态再结晶模型

Deformation Behavior and Dynamic Recrystallization Model for 690 Alloy

摘要:

利用物理模拟实验方法对690合金进行恒温恒速压缩实验，变形温度范围为1050~1250 ℃，应变速率分别为0.1, 1、5, 10 s-1，获得了合金的流变应力数据，并对合金变形后的组织特征进行了分析。建立了690合金高温热变形的本构方程和动态再结晶模型。结果表明： 690合金高温变形时的流变行为可用Zener-Hollomon参数的双曲正弦函数来描述，所建立流变应力本构模型的预测值与实验值吻合较好，建立了690合金的动态再结晶模型，为热挤压过程中的组织控制提供理论依据

关键词:690合金;高温变形;本构关系;动态再结晶模型

Abstract:

The flow stress behaviors and microstructure characteristics of 690 alloy were investigated by isothermal compression tests in the temperature range of 1050-1200 °C and strain rate range of 0.1-10 s-1 on Gleeble 1500 thermo-simulation machine. The flow stress constitutive equation and dynamic recrystallization model of 690 alloy during hot compression was established. The results show that the flow stress can be represented by a Zenner-Hollomon parameter in the hyperbolic sine type equation. The flow stress of 690 alloy predicted by the proposed models well agrees with experimental results. Therefore, the proposed model can provide the references for the microstructure control during hot extrusion process

Key words:690 alloy; hot deformation; constitutive relationship; dynamic recrystallization model