Study on the Phase Formation Law and Hot Deformation Behavior of Al-0.8Mg-0.9Si-0.4Mn-0.6Cu Alloy for Rail Vehicles

本文以轨道车辆用Al-0.8Mg-0.9Si-0.4Mn-0.6Cu合金为研究对象，通过热力学相图计算与热压缩实验，探索了该合金的相形成规律与热变形行为。利用Pandat软件预测了平衡与非平衡凝固路径，揭示了Mg2Si、Q相等强化相的析出顺序与热稳定性，并探讨了Fe/Mn杂质相的演化机制。通过440℃下的热压缩实验，考察了不同应变速率(0.01~30 s⁻¹)下的流变行为，明确了动态回复、动态再结晶与加工硬化的竞争关系随应变速率变化的依赖性；研究结果可为该合金组织性能调控与成形工艺优化提供了理论支支撑。This study focuses on the Al-0.8Mg-0.9Si-0.4Mn-0.6Cu alloy used in rail vehicles. Through thermos-dynamic phase diagram calculations and hot compression experiments, the phase formation behavior and hot deformation characteristics of this alloy are explored. The equilibrium and non-equilibrium solidification paths were predicted using Pandat software, revealing the precipitation sequence and thermal stability of strengthening phases such as Mg2Si and the Q phase. Additionally, the evolution mechanism of Fe/Mn impurity phases was discussed. Hot compression experiments at 440˚C were conducted to investigate the rheological behavior at different strain rates (0.01~30 s⁻¹), clarifying the dependence of dynamic recovery, dynamic recrystallization, and work hardening on strain rate. The results provide theoretical support for the microstructure-property regulation and process optimization of this alloy.