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通过弯边变形,拉伸实验,OM,SEM和TEM观察等手段研究了不同浓度富Fe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Fe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Fe相粒子的合金板材沿2个方向弯边变形180°后外表面粗糙度增加,处于中等浓度(含0.2%Fe)时沿2个方向弯边变形后均具有优异的外表面质量,但是随着富Fe相浓度的进一步增加(至0.5%Fe),合金板材沿横向弯边变形后在外表面出现微裂纹.虽然富Fe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Fe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Fe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Fe相粒子的尺寸、形态以及分布状态密切相关.此外,根据不同浓度富Fe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 effects of different concentrations of Fe-rich phase particles on the crimp properties of Al-Mg-Si-Cu alloy sheets were studied by means of bending deformation, tensile test, OM, SEM and TEM observations. The results show that with the increase of Fe When the phase concentration increases, there is a big difference in the bending properties of the alloy sheet along the longitudinal and transverse directions. The surface roughness of the alloy sheet without the Fe-rich phase particles after being deformed by 180 ° in two directions increases to a moderate concentration (containing 0.2% Fe) showed excellent external surface quality after bending in both directions. However, with the further increase of the Fe-rich phase concentration (up to 0.5% Fe), micro-cracks appeared on the outer surface of the alloy plate along the lateral bending deformation. Although the increase of Fe-rich phase concentration has little effect on the longitudinal and transverse elongation of the alloy sheet, the tensile fracture, the bending and the lateral surface microstructure after tensile fracture all show that the alloy sheet without Fe-rich phase is deformed The increase of surface roughness is closely related to the microstructure of the shear band. However, the micro-cracks appearing on the outer surface of the alloy plate with higher concentration of Fe-rich phase are closely related to the size, morphology and distribution of the coarse Fe-rich phase. In addition, depending on the concentration of Fe-rich The relationship between phase particles and the properties of the alloy was studied. The model diagram of the increase of surface roughness and the formation of microcracks after the deformation of the alloy was proposed.