2D70铝合金热变形动态组织演变及模型研究

Microstructure Evolution and Model of 2D70 Aluminum Alloy during Hot Deformation

针对2D70铝合金进行等温恒应变速率压缩试验,分析合金在应变速率为0.001~1s^(-1),温度为350~530℃下变形的流变应力曲线和显微组织演变。基于此,建立2D70铝合金在该变形条件下的流变应力方程和位错密度模型,并利用DEFORM-3D有限元软件对合金进行微观组织模拟。结果表明,2D70铝合金在350℃下变形时,由于内部组织发生动态再结晶,使得在较低应变速率下(0.001s^(-1))变形的组织晶粒更细小;当变形温度达到470℃时,α-Al_2CuMg相大量回溶基体,呈现出α-Al相晶粒,其尺寸随着应变速率的提高而减小,同时在较低应变速率(0.001s^(-1))下变形,α-Al相晶粒将变得粗大。模拟对比可知模拟组织较好地反映金相组织演变趋势。

Stress-strain curves and microstructure evolution of 2D70aluminum alloy were analyzed by isothermal constant strain rate compression deformation test at 350-530℃and strain rate of 0.001-1s^-1.The flow stress equation and dislocation density model of 2D70aluminum alloy were established under the given conditions.And DEFORM-3Dfinite element software was used to simulate the microstructure of the alloy.The results show that the dynamic recrystallization of 2D70aluminum alloy at 350℃can result in the more refinement of alloy grains under a lower strain rate（0.001s^-1）.The S-Al_2CuMg phase is decreased greatly to be dissolved into the matrix and theα-Al phase grains is decreased gradually with increasing in strain rate when the deformation temperature reaches 470℃.The size ofα-Al phase is decreased with increasing in strain rate.Theα-Al phase grains are coarsened with deformed at a lower strain rate（0.001s^-1）.Simulation comparison reveals that the grains in the simulated microstructure are well in agreement with the evolution of metallographic microstructure.