Zr-1.0Sn-1.0Nb-0.1Fe合金热变形行为及动态再结晶模型建立

Hot Deformation Behavior and Dynamic Recrystallization Modeling of Zr-1.0Sn-1.0Nb-0.1Fe Alloy

热轧过程中的动态再结晶影响锆合金板材的组织、织构演化以及最终力学性能。在本研究中,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0.01~10 s^(-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。

Dynamic recrystallization(DRX) affects the microstructure, texture evolution and final mechanical properties of zirconium alloys during hot rolling. In this study, hot compression tests wer e performed on Gleeble 3800 tester at temperatures between 550 oC and 700 oC with strain rates between 0.01 sand 10 sto investigate dynamic recrystallization behavior of Zr-1.0Sn-1.0Nb-0.1Fe. Critical strains for initiation of dynamic recrystallization and peak strains were identified through the analysis of work hardening rate from measured stress-strain results. Dynamic recrystallization was 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 was modeled using calculated critical strain, peak strain, and volume fraction of dynamic recrystallization. Finally, the dynamic recrystallization model of Zr-1.0Sn-1.0Nb-0.1Fe was verified by the volume fraction of dynamic recrystallization measured from electron backscattered diffraction results.