The dynamic recrystallization (DRX) behavior of austenite in reduced activation ferritic/martensitic steel was investigated by isothermal compression tests and constitutive modelling. The flow stress decreases with deformation temperature increasing and strain rate decreasing. The constitutive equations were constructed based on the analysis by Arrhenius equations. Based on the dynamic material model, the hot processing map was constructed. In the stability region, the power dissipation efficiency (η) increases with increasing strain, and the softening is dominated by DRX when η grows to a specific value. However, η decreases as strain increases further after the complete evolution of DRX, indicating coarsening of DRXed grains. As the strain increases, the processing stability region shifts to the low temperature and high strain rate region. A novel recrystallization kinetics model was developed by considering the characteristics of the recrystallization velocity with strain increasing. It can reflect the "slow-rapid-slow" growth trend of recrystallization volume fraction (X_DRX). The relationship between X_DRX and $\overline{D}$ (average grain size of austenite) was constructed, which indicates that $\overline{D}$ decreases with strain increasing after the onset of DRX. When X_DRX is greater than 50%, the decrease rate of $\overline{D}$ slows down until the steady-state is reached. Although strain increase further, the grain size remains constant. This suggests that the expected $\overline{D}$ can be obtained by controlling X_DRX during hot deformation.

通过等温压缩试验和本构模型研究了减少活化铁素体/马氏体钢中奥氏体的动态再结晶 (DRX) 行为。流变应力随着变形温度的升高和应变速率的降低而降低。本构方程是根据Arrhenius方程的分析构建的。基于动态材料模型，构建热加工图。在稳定区，功率耗散效率 ( η) 随着应变的增加而增加，当 η 增长到特定值时，软化由 DRX 主导。然而，在 DRX 完全演化后，随着应变进一步增加，η 减小，表明 DRX 晶粒粗化。随着应变的增加，加工稳定性区域转移到低温和高应变率区域。考虑再结晶速度随应变增加的特点，建立了一种新的再结晶动力学模型。它可以反映再结晶体积分数（X _DRX）的“慢-快-慢”增长趋势。X _DRX和$\overline{D}$ （奥氏体的平均晶粒尺寸）被构造，这表明 $\overline{D}$在 DRX 开始后，随着应变的增加而降低。当 X _DRX大于 50% 时，下降率$\overline{D}$减速直至达到稳态。尽管应变进一步增加，但晶粒尺寸保持不变。这表明预期$\overline{D}$可以通过在热变形过程中控制 X _DRX来获得。