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在变形温度为350~510℃、应变速率为0.001~10 s-1条件下，在 Gleeble-3500热模拟实验机上对 Al-Mg-Si-Ti合金进行等温热压缩实验，以实验所得数据为基础，结合变形微观组织，确定了 Al-Mg-Si-Ti 合金热变形时发生动态再结晶的条件，建立了 Al-Mg-Si-Ti合金动态再结晶峰值应变模型。采用加工硬化率的方法，利用 lnθ-ε曲线的拐点特征和-?(lnθ)/?ε-ε曲线的极小值判据对再结晶峰值应变与临界应变关系进行了研究。结果表明：Al-Mg-Si-Ti合金热变形时在变形温度430~510℃、应变速率0.001~0.1 s-1发生动态再结晶。Al-Mg-Si-Ti 合金发生动态再结晶时的临界应变随应变速率的增大而增加，随变形温度的升高而降低。临界应变与峰值应变满足关系：εc=0.88εp。

Hot compression tests of Al-Mg-Si-Ti alloy has been investigated by Gleeble-3500 thermo-mechanical system at 350-510 ℃ and strain rate of 0.001-10 s-1 .Based on the experiment data and deformation microstruc-ture,the condition of dynamic recrystallization of Al-Mg-Si-Ti alloy during hot deformation process was determined and the peak strain model of dynamic recrystallization was established.The relationship between peak strain and criti-cal strain was studied by the rate of working hardening,the inflection point criterion of lnθ-εcurves and the minimum value criterion of -?(lnθ)/?ε-εcurves.The results showed that the dynamic recrystallization of Al-Mg-Si-Ti alloy oc-curred at the temperature of 430-510 ℃ and the strain rate of 0.001-0.1 s-1 .The dynamic recrystallization critical strain increased with the increasing strain rate and the decreasing deformation temperature.The relationship between the dynamic recrystallization critical strain and the peak strain could be described asεc=0.88εp .