Sc微合金化对6061铝合金性能及微观结构的影响
王 红1，张德宇1，王 斌1，孙啸飞2，陆起高2，王 征2*，王双宝1*
（1.云南大学材料与能源学院，云南大学电镜中心，云南 昆明 650091；2. 云南云铝泽鑫铝业有限公司，云南 曲靖 655500）摘 要 6000系铝合金凭借其出色的性能，包括较高的强度比、良好的成形性以及优异的耐腐蚀性，在汽车制造、航空航天及建筑领域得到了广泛应用。为适应航空航天、汽车等领域对结构材料轻量化、耐腐蚀及高强度的综合需求，研发综合性能更优的铝合金材料已成为当前材料科学领域的重要研究方向。本文以6061（Al-0.5Mg-0.4Si-0.3Cu，wt.%）为参考合金，利用扫描电子显微术和透射电子显微术系统研究了T6（固溶+淬火+人工时效）热处理工艺制度下0.2wt.% Sc的微合金化元素添加对其性能和微观组织的影响。结果表明，Sc的微添加显著提升了6061合金的硬度、延伸率、耐热性能和抗腐蚀性能。6061-Sc合金硬度和延伸率的提升归因于铝基体晶粒和粗大组分相颗粒（包括Si颗粒、FeSi2和Mg2Si）尺寸的细化。Sc元素的添加使6061合金中主要纳米析出强化相Q'（Al3Cu2Mg9Si7）部分转变为耐热性能好的C相（Mg4Al1Si3+xCu1-x, x~0.3）、细化了析出相尺寸并增加了数量密度，提高了6061合金的硬度和耐热性能。与6061合金相比，6061-Sc合金抗腐蚀性能的提高主要是由于Sc减小了晶界无析出带的宽度。研究结果可为Sc微合金化的高性能铝合金设计提供理论和实验基础。
关键词 6061铝合金；Sc微合金化；微观结构；性能；电子显微术
中图分类号：TG146.21；TG156.92 文献标识码：A Doi:10.3969/j.issn.1000-6281.2025.05.007
Effect of Sc microalloying on properties and microstructure of 6061
Al alloy
WANG Hong1，ZHANG Deyu1，WANG Bin1，SUN Xiaofei2，LU Qigao2，WANG Zheng2*，WANG Shuangbao1*
(1. School of Materials and Energy, Electron Microscopy Center, Yunnan University, Kunming Yunan 650091; 2. Yunnan Yunlü Zexin Aluminum Industry Co., Ltd, Qujing Yunan 655500, China)
Abstract The 6000 series aluminum alloys are widely used in automotive manufacturing, aerospace, and construction due to their excellent combination of high strength-to-weight ratio, good formability, and superior corrosion resistance. To meet the increasing demand for lightweight, corrosion-resistant, and high-strength structural materials in aerospace, automotive, and related fields, developing aluminum alloys with enhanced comprehensive performance has become a key research focus in material science. This study uses 6061 alloy (Al-0.5Mg-0.4Si-0.3Cu, wt.%) as a baseline and systematically investigate the effects of microalloying with 0.2wt.% Sc on its properties and microstructure under T6 heat treatment (solid solution, quenching, and artificial aging), utilizing scanning electron microscopy and transmission electron microscopy. The results showed that the addition of Sc significantly improved the hardness, elongation, heat resistance, and corrosion resistance of the 6061 alloy. The improvement in hardness and elongation was attributed to grain refinement of the Al matrix and coarse constituent particles (including Si particles, FeSi2, and Mg2Si). Sc addition transformed the primary nanoprecipitates from Q' phase (Al3Cu2Mg9Si7) in 6061 alloy to a heat-resistant C phase (Mg4Al1Si3+xCu1-x, x~0.3), refining the precipitate size and increasing their number density, and improving hardness and heat resistance. The improved corrosion resistance of the 6061-Sc alloy was mainly due to the reduction in the width of the grain boundary precipitation free zone induced by Sc. These results provide theoretical and experimental insight for designing high-performance Al alloys with Sc microalloying.
Keywords 6061 Al alloy; Sc microalloying; microstructure; property; electron microscopy
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