由于对热处理工艺存在依赖，传统铝合金普遍面临能耗高、变形大等工程挑战，这一现状促使免热处理铝 合金得以快速发展。 本文基于JMatPro热力学计算，优化Al-7Si-Mg-Cu-Mn合金成分体系，揭示稀土Ce调控微观组织 的热力学机制，为新型免热处理铝合金的开发提供理论支撑。CALPHAD计算表明，将Mg/Cu质量比控制在1.53时，可 促进Q相(Al5 Cu2 Mg8 Si6 )成为主导强化相，取代 Mg2 Si 和 Al2 Cu 相，实现强度-塑性协同提升。 在优化后的基体合金中添 加稀土Ce可进一步强化合金性能。 结合实验及偏摩尔吉布斯自由能计算，阐明了Ce微合金化的调控机制：Ce在凝固 过程中降低α-Al 形核势垒并抑制枝晶生长，使二次枝晶臂间距降低34.2%；在共晶阶段，Ce选择性吸附在硅相表 面，促使共晶硅形貌由层片状转变为纤维状。 该协同优化效应在Ce含量为0.3%(质量分数)时达到峰值，合金抗拉强度 (179 MPa)和伸长率(7.4%)较未添加 Ce 的合金分别提升了17%和51%。

 Traditional aluminium alloys, owing to their reliance on heat treatment processes, generally suffer from high energy consumption and significant deformation, which has driven the rapid development of non-heat treatment aluminium alloys. The composition of the Al-7Si-Mg-Cu-Mn alloy was optimized on the basis of JMatPro thermodynamic calculations, and the thermodynamic mechanism of the rare earth Ce in regulating the microstructure was revealed, providing theoretical support for the development of new non-heat treatment aluminium alloys. Through CALPHAD phase diagram calculations, it is found that controlling the Mg/Cu mass ratio to 1.53 can promote the formation of the Q phase (Al5 Cu2 Mg8 Si6 ) as the dominant strengthening phase, replacing the Mg2 Si and Al2 Cu phases, thereby achieving a synergistic improvement in strength and ductility. The addition of rare earth Ce to the optimized base alloy further enhances its performance. The mechanism of Ce microalloying is elucidated through experimental analysis and partial molar Gibbs free energy calculations: During solidification, Ce reduces the nucleation barrier of α-Al and inhibits dendritic growth, leading to a 34.2% reduction in secondary dendrite arm spacing; during the eutectic reaction stage, Ce selectively adsorbs on the silicon phase surface, transforming the eutectic silicon morphology from flake-like to fibrous. This synergistic optimization effect peaks at a Ce content of 0.3 wt.%. At this level, the alloy exhibits a tensile strength of 179 MPa and an elongation of  7.4%, representing increases of 17% and 51%, respectively, compared with those of the alloy without Ce. However, when the Ce content exceeded 0.3 wt.%, the coarsening of the Al-Si-Ce rare earth phases results in a decrease in the mechanical properties.