在铝合金铸轧成型过程中，通过促进或抑制粒子刺激形核(PSN)效应调控铝合金再结晶行为，改善铝合金的组织结构，是制备高质量铸轧板的技术关键和难点。本工作制备了6种不同Zr含量的Al-Mg-Si铸轧薄板，旨在从PSN角度揭示Zr含量对Al-Mg-Si铸轧薄板再结晶行为和力学性能的影响机理。结果表明，随着Zr含量的增加，晶粒尺寸呈先增大后减小再增大的变化趋势。Zr元素可与Al元素结合形成L1₂结构的纳米级Al₃Zr析出相，抑制铸轧板PSN再结晶行为，促使晶粒纤维化。当Zr添加量为0.4% (质量分数，下同)时，晶粒纤维化程度最大；当Zr含量为0.6%时，Zr元素对晶粒再结晶的抑制作用减弱，微观组织中出现粗大D0₂₃结构的Al₃Zr初生相，加剧了铸轧板的再结晶程度，再结晶晶粒明显长大。此外，随着铸轧板中Zr含量的增加，富Fe相的尺寸、体积分数均呈先增大后减小再增大的变化趋势。当Zr含量为0.3%时,铸轧板的综合力学性能较佳，此时拉伸断口呈现韧性断裂特征，铸轧板中富Fe相呈弥散分布，板材的抗拉强度、屈服强度和延伸率分别为226.91 MPa、104.81 MPa、15.05%。

Twin roll casting is a short-process, high-energy-efficiency method for producing aluminum alloy sheets. During the forming process of cast-rolled aluminum alloy sheets, defects such as segregation, coarse secondary phases, and poor properties may occur owing to the quenching effect of the rolling mill rolls. Microalloying can effectively mitigate these defects and enhance the mechanical properties of aluminum alloy sheets produced by cast rolling. In the aluminum alloy twin roll casting process, regulating the recrystallization behavior and improving the microstructure by promoting or suppressing the particle-stimulated nucleation (PSN) effect is critical for producing high-quality cast-rolled sheets. This study prepared six Al-Mg-Si cast-rolled aluminum alloy sheets with varying Zr contents to investigate the evolution of their microstructure and properties, aiming to reveal the influence of Zr content on the recrystallization behavior and mechanical properties of Al-Mg-Si cast-rolled aluminum alloy sheets from the perspective of PSN. The results demonstrated that as the Zr content increased, the grain size initially increased, subsequently decreased, and then increased again. The Zr element was observed to combine with Al to form nano-sized Al₃Zr precipitates with L1₂ structure. These precipitates effectively inhibited the recrystallization behavior associated with PSN in cast-rolled sheets and promoted grain fibrosis. Specifically, when the Zr content was 0.4% (mass fraction), the degree of grain fibrosis reached its maximum; however, with a Zr content of 0.6%, the inhibitory effect of Zr on grain recrystallization was reduced. At this concentration, the coarse D0₂₃-structured Al₃Zr primary phase emerged, exacerbating the PSN effect and increasing the degree of recrystallization in the cast-rolled sheet. Furthermore, as the Zr content increased in the cast-rolled sheet, the size and volume fraction of the Fe-rich phase exhibited a trend of first increasing, then decreasing, and subsequently increasing again. Notably, when the Zr content was 0.3%, the comprehensive mechanical properties of the cast-rolled sheet were optimal. The tensile fracture surface exhibited ductile fracture characteristics, and the Fe-rich phase distribution in the sheet was dispersed. The tensile strength, yield strength, and elongation were measured to be 226.91 MPa, 104.81 MPa, and 15.05%, respectively.