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利用永磁搅拌近液相线铸造和普通铸造方法制备不同晶粒尺寸的2024铝合金铸锭,利用Gleeble-1500热模拟试验机研究初始晶粒尺寸对不同压缩变形条件下2024铝合金的热变形行为和变形后显微组织的影响。研究表明:2024铝合金的热变形行为依赖于变形条件和初始组织。初始晶粒尺寸对流变应力的影响是:当应变速率小于0.1 s~(-1)时,流变应力随晶粒尺寸减小而减少;当应变速率为10 s~(-1)时,流变应力随晶粒尺寸减小而增大。降低变形温度会弱化晶粒尺寸对流变应力的影响。热压缩流变应力随应变速率增大而增大,随变形温度升高而减小。应变速率为10 s~(-1)时,热压缩应力应变曲线呈现周期性波动;只在粗晶2024铝合金中发现变形剪切带。
2024 aluminum alloy ingot with different grain size was prepared by permanent magnetic stirring near liquidus casting and ordinary casting method. The thermal deformation of 2024 aluminum alloy under different compressive deformation was studied by using Gleeble-1500 thermal simulation tester. Behavioral and post-distortion microstructural effects. The results show that the thermal deformation behavior of 2024 aluminum alloy depends on the deformation conditions and initial microstructure. The effect of initial grain size on the flow stress is that when the strain rate is less than 0.1 s ~ (-1), the flow stress decreases with the decrease of the grain size. When the strain rate is 10 s ~ (-1) The stress increases with decreasing grain size. Decreasing the deformation temperature will weaken the effect of grain size on the flow stress. Hot compression flow stress increases with the strain rate increases, with the deformation temperature decreases. When the strain rate is 10 s ~ (-1), the stress - strain curve of the hot compressive strain fluctuates cyclically; the deformed shear band is only found in the coarse grain 2024 aluminum alloy.