基于Laasraoui-Jonas位错密度模型的GWZK134合金动态再结晶行为研究

    Research on Dynamic Recrystallization Behavior of GWZK134 Alloy Based on Laasraoui-Jonas Dislocation Density Model

    • 摘要: 采用Gleeble-3500D热模拟试验机进行了单轴等温压缩试验,研究了GWZK134合金在变形温度360~480℃,应变速率0.001~1 s-1条件下的动态再结晶行为,并基于镁合金的密排六方(HCP)结构,建立了改进的Laasraoui-Jonas(L-J)位错密度模型。结果表明:GWZK134合金的动态再结晶体积分数随温度的升高而增大,随应变速率的加快而减小。在变形过程中,动态再结晶由晶界处形核产生,并逐步向周围晶粒扩展,随温度升高或应变速率的降低,压缩条件下剪切应力引起的扁平状晶粒逐渐成为等轴晶。此外,通过模拟仿真结果与试验数据相比较,证明所建立的模型对该合金动态再结晶行为模拟较为准确。

       

      Abstract: A uniaxial isothermal compression test was performed using Gleeble-3500D thermal simulation testing machine, and the dynamic recrystallization behavior of the GWZK134 alloy at deformation temperature of 360 ℃ to 480 ℃ and strain rate of 0.001 s-1to 1 s-1 was studied.Based on the hexagonal closepacked (HCP) structure of magnesium alloy, an improved model of Laasraoui-Jonas (L-J) dislocation density was established. The results show that the dynamic recrystallization volume fraction of GWZK134 alloy increases with increasing temperature and decreases with increasing strain rate.During the deformation process, the dynamic recrystallization occurs from nucleation at the grain boundaries, and gradually expands to the surrounding grains.As the temperature increases or the strain rate decreases, the flat grains caused by shear stress under compression conditions gradually become equiaxed. The comparison between numerical simulation and experimental data shows that the established model is more accurate in studying the dynamic recrystallization behavior of the alloy.

       

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