通过弯边变形、拉伸实验、OM、SEM、TEM观察等手段研究了不同浓度富铁相粒子对Al-Mg-Si-Cu系合金板材弯边性能的影响规律。结果表明，随着富铁相浓度增加，合金板材沿纵横向的弯边性能存在较大差异，不含富铁相粒子的合金板材沿两个方向弯边变形180°后外表面粗糙度增加，处于中等浓度（含0.2wt%Fe）时沿两个方向弯边变形后均具有优异的外表面质量，但是随着富铁相浓度的进一步增加（至0.5wt%Fe），合金板材沿两个方向弯边变形后均在外表面出现微裂纹。虽然富铁相粒子浓度增加对合金板材纵横向延伸率影响不大，但是拉伸断口、弯边和拉伸断裂后的侧表面组织均表明，不含富铁相的合金板材弯边变形后外表面粗糙度增加与剪切带组织密切相关，而含有较高浓度富铁相粒子的合金板材弯边变形后外表面出现的微裂纹与粗大富铁相粒子的尺寸、形态以及分布状态密切相关。此外，本文根据不同浓度富铁相粒子与合金弯边性能间的定量关系提出了合金弯边变形后外表面粗糙度增加和微裂纹形成的模型示意图。

The influence of iron-rich phase particle with different contents on the bendability of the Al-Mg-Si-Cu alloys was investigated by means of bending and tensile tests, OM, SEM and TEM characterization. The results reveal that, with the increase of iron-rich phase particle content, the bendability of the alloy sheets in the longitudinal and transverse directions is quite different, and the outer surface of the alloy sheets after bending of 180° along the two directions becomes much rough, especially along the transverse direction. When the iron-rich phase concentration increases to the medium level (0.2wt% Fe), the quality of outer surface after bending is very good. But with further increasing iron-rich phase to the high level (0.5wt% Fe), micro cracks can be produced after bending along the two directions. Although increasing iron-rich phase concentration does not give a great effect on the elongation of the alloys in the two directions, yet, according to the tensile fracture and microstructure in the slid surface of the specimen after bending or tension test, the roughening of outer surface of the alloy sheet without ion-rich phase is closely related with the formation of shear bands, while for the alloy sheet with high concentration of ion-rich phases, the formation of micro cracks after bending is mainly related with the size, morphology and distribution of coarse iron-rich phases. In addition, based on the quantitative relationship between iron-rich phase concentration and bendability of the alloy sheets, the models of outer surface roughening and micro cracks forming during bending were also put forward in this paper.