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采用Gleebe-3500热模拟试验机在变形温度350℃~500℃,应变速率0.01s~(-1)、0.1s~(-1)、1s~(-1)和5s~(-1),最大变形量60%的条件下对近共晶Al-Mg-Si、Al-Mg-Si-Ti合金进行等温热压缩模拟研究。建立了两种近共晶合金的高温流变本构方程和热加工图,并结合EBSD微观组织分析了Ti对近共晶Al-Mg-Si合金高温流变行为的影响。研究结果表明,可用含Arrhenius项的Z参数描述两种合金高温变形时的流变行为;并基于热加工图得出Al-Mg-Si合金优化的工艺参数为变形温度475℃~500℃,变形速率0.01s-1,Al-Mg-Si-Ti合金优化的工艺参数为变形温度450℃~475℃,变形速率0.1s~(-1);同时发现含Ti第二相颗粒会在高温塑性变形过程中阻碍位错运动,抑制动态再结晶软化,提高合金高温流变应力和形变激活能。
The Gleebe-3500 thermal simulator was used to test the mechanical properties at the deformation temperature of 350 ℃ ~ 500 ℃, the strain rate of 0.01s ~ (-1), 0.1s ~ (-1s) and 5s ~ (-1) The isothermal hot compression simulation of near-eutectic Al-Mg-Si and Al-Mg-Si-Ti alloys under 60% deformation was carried out. The rheological constitutive equation and hot working diagram of two near-eutectic alloys were established. The influence of Ti on the rheological behavior of Al-Mg-Si alloy at high temperature was analyzed by EBSD microstructure. The results show that the Arrhenius term Z parameter can be used to describe the rheological behavior of the two alloys at high temperature deformation. Based on the hot working diagram, the optimum technological parameters of the Al-Mg-Si alloy are the deformation temperature 475 ℃ ~ 500 ℃, deformation The rate of 0.01s-1, Al-Mg-Si-Ti alloy optimization process parameters for the deformation temperature 450 ℃ ~ 475 ℃, deformation rate 0.1s ~ (-1); also found that the second phase particles containing Ti will be plastic deformation During the process, dislocation movement is hindered, dynamic recrystallization softening is inhibited, and high temperature flow stress and deformation activation energy of the alloy are increased.