(中南大学 粉末冶金国家重点实验室, 长沙 410083)
摘 要: 设计了铝合金铸轧工艺模拟的实验装置，研究了在该试验条件下， 铝合金变形组织与工艺参数的关系。 结果表明： 按照本试验的设计， 在夹头通水冷却的Gleeble-1500热模拟机上能够得到铝的“人”字形特征的柱状晶组织， 实现铸轧组织的物理模拟过程。 铝合金模拟铸轧的显微组织对外力施加的应变速率很敏感： ε·=0.125s-1时， 变形开始与凝固过程发生耦合， 铸轧组织发生转变； 应变速率增大至ε·=0.300s-1时， 铸轧柱状晶发生等轴化。 铸轧组织的形成主要是变形作用于未凝固的液相，引起质量和热量的分布状态发生改变所致。 提高铸轧速度， 有利于铸轧组织的形成和铸轧柱状晶的等轴化， 并且使所需的轧制力减小， 有利于铸轧工艺的优化。
关键字: 铝合金；铸轧； 物理模拟； 显微组织
（State Key Laboratory for Powder Metallurgy,
Central South University, Changsha 410083, China）
Abstract:An experimental instrument for simulating the roll-casting process was designed, and the effect of processing parameters on the microstructure of Al alloy was studied. Results show that with a specifically designed instrument equipped in a Gleeble-1500 Thermal Simulation Tester the typical microstructure with the characteristic of realistic roll-casting process can be obtained, and the microstructure is sensitive to the strain rate. When ε·=0.125s-1, the plastic deformation of Al alloy starts to couple with the solidification process, and the microstructure is of the roll-casting character. Whenε·=0.300s-1, the column crystals transform to equiaxed ones. The formation of roll-casting microstructure is mainly attributed to the deformation of un-solidified liquid phase, the varied distribution of mass and heat. Increasing the deformation velocity would do good to the formation of roll-casting microstructure and the equiaxed column crystals, and would decrease the rolling load.
Key words: roll-casting; Al alloy; physical simulation; microstr
