Choi Kwangmin, Lee Sangjun, Bae Donghyun
Department of Materials Science and Engineering, Yonsei University, Seoul 03722, Republic of Korea.
Institute of Industrial Science, The University of Tokyo, 4-6-1 Komaba, Meguro 153-8505, Tokyo, Japan.
Materials (Basel). 2024 Sep 12;17(18):4478. doi: 10.3390/ma17184478.
This study investigated the effects of aging profiles on the precipitate formation and the corresponding strengthening and deformation behaviors of Al-Mg-Zn alloys. The alloys subjected to natural aging (NA) demonstrated significantly enhanced ductility at equivalent stress levels compared to those subjected to artificial aging (AA). In AA-treated alloys, η' and η-phases with incoherent interfaces were formed, while GP zones and solute clusters were dominantly exhibited in the NA-treated alloy with a coherent interface with the matrix. Due to the change in interface bonding, the dislocation movement and pinning behavior after deformation are varied depending on the aging conditions of Al-Mg-Zn alloy sheet. Thus, the elongation to fracture of the NA alloy sheet was improved compared to that of the AA alloy sheet because of the enhanced work-hardening capacity and the thin precipitate-free zone (PFZ). Deformation textures and dislocation densities varied between NA and AA treatments, as revealed by electron backscatter diffraction (EBSD) and kernel average misorientation (KAM) analysis. The interactions between the precipitates, dislocations, and the PFZ in the AA- and NA-treated alloys were analyzed via transmission electron microscopy (TEM). The insights gained from this research provide a valuable foundation for industrial applications, particularly in sectors demanding lightweight, high-strength materials, where optimizing the aging process can lead to significant performance improvement and cost savings.
本研究调查了时效曲线对Al-Mg-Zn合金中析出相形成以及相应的强化和变形行为的影响。与经过人工时效（AA）的合金相比，经过自然时效（NA）的合金在等效应力水平下表现出显著提高的延展性。在经过AA处理的合金中，形成了具有非共格界面的η'相和η相，而在与基体具有共格界面的经过NA处理的合金中，主要表现为GP区和溶质团簇。由于界面结合的变化，Al-Mg-Zn合金板材变形后的位错运动和钉扎行为因时效条件而异。因此，由于加工硬化能力增强和无析出带（PFZ）变薄，NA合金板材的断裂伸长率比AA合金板材有所提高。如电子背散射衍射（EBSD）和核平均取向差（KAM）分析所示，NA处理和AA处理之间的变形织构和位错密度有所不同。通过透射电子显微镜（TEM）分析了经过AA处理和NA处理的合金中析出相、位错和PFZ之间的相互作用。本研究获得的见解为工业应用提供了宝贵的基础，特别是在需要轻质、高强度材料的领域，优化时效工艺可显著提高性能并节省成本。
