Zr-1.0Sn-1.0Nb-0.1Fe合金热变形行为及动态再结晶模型建立

Modeling Dynamic Recrystallization Behavior of Zr-1.0Sn-1.0Nb-0.1Fe alloy During Hot Deformation

摘要:

热轧过程中的动态再结晶影响锆合金板材制备过程中的组织和织构遗传性,以及最终力学性能。在本文中,利用Gleeble 3800热模拟实验研究了Zr-1.0Sn-1.0Nb-0.1Fe合金在应变速率为0.01~10s_^-1范围下,变形温度在550℃~700℃的动态再结晶行为。通过对实测应力-应变结果的加工硬化速率分析,确定了动态再结晶开始发生的临界应变和峰值应变。动态再结晶是通过塑性变形过程中流变应力的软化来判断的,并量化为计算的动态回复曲线和实测的应力应变曲线之间的差异。采用计算的临界应变、峰值应变、Zener-Hollomon参数和动态再结晶体积分数对动态再结晶过程进行建模,最终利用EBSD统计所得的再结晶体积分数验证了Zr-1.0Sn-1.0Nb-0.1Fe合金的动态再结晶模型。

Abstract:

Dynamic recrystallization (DRX) affects the microstructure, texture evolution and final mechanical properties of zirconium alloys during hot rolling. In this study, hot compression tests are performed at temperatures between 550 ℃and 700℃ with strain rates between 0.01s_^-1 and 10s_^-1 to investigate dynamic recrystallization behavior of Zr-1.0Sn-1.0Nb-0.1Fe. Critical strains for initiation of dynamic recrystallization and peak strains are identified through the analysis of work hardening rate from measured stress-strain results. Dynamic recrystallization is identified by the softening in the flow stress during plastic deformation and quantified as the difference between a calculated dynamic recovery curve and the measured stress-strain curve. Dynamic recrystallization is modeled using calculated critical strain, peak strain, Zener-Hollomon (Z) parameter, and volume fraction of dynamic recrystallization. Finally, the dynamic recrystallization model of Zr-1.0Sn-1.0Nb-0.1Fe was verified by flow stress curves and volume fraction of dynamic recrystallization.