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微量 Sc 添加对 Al-Mg-Si-Cu 合金微观组织及 力学性能的影响
Effect of the Microaddition of Sc on the Microstructure and Mechanical Properties of Al-Mg-Si-Cu Alloy
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- DOI:
- 作者:
- 陈向荣 1，陈忠伟 1，汪泽瑾 2，安 博 1，张浩岚 1，曾 毅 2，牛虎明 2，姜万明 2
CHEN Xiangrong1, CHEN Zhongwei1, WANG Zejin2, AN Bo1, ZHANG Haolan1, ZENG Yi2, NIU Huming2, JIANG Wa
- 作者单位:
- 1. 西北工业大学 凝固技术全国重点实验室，陕西 西安 710072；2. 陕西有色榆林新材料集团有限责任公司，陕西 榆林 719099
1. State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi'an 710072, China; 2. Shaanxi Nonferrous Yulin New Material Group, Yulin 719099, China
- 关键词:
- Al-Mg-Si-Cu 铝合金；稀土元素 Sc；微观组织；力学性能
Al-Mg-Si-Cu aluminium alloy; rare earth element Sc; alloy microstructure; mechanical properties
- 摘要:
- 汽车轻量化对 6 系铝合金的力学性能提出了更高的要求，因此急需开发高强高韧性 6 系铝合金满足日益增长的需求。 通过扫描电镜、透射电镜和万能力学试验机研究了添加 0.4%Sc(质量分数，下同)对 Al-Mg-Si-Cu 合金微观组织及力学性能的影响。 结果表明，添加 0.4%Sc 可显著细化铸态合金显微组织，使铸态合金从粗大柱状晶转变为细小等轴晶， 铸态合金显微组织更加均匀。 铸态合金中脆性相 β-AlFeSi 在 Sc 微合金化后形态发生转变， 粗大的片层状β-AlFeSi 相 转变 为 细 针 状 。 添加 0.4%Sc 的 固溶+时效 热 处 理 轧 制 态 合 金 中 ， 主要 析 出 相 包 括 次 生 Al3Sc 相 Q′相(Al3Cu2Mg9Si7)及 β″相(Mg5Si6)，3 种析出相协同作用对合金产生了综合强化效果。 添加 0.4%Sc 使得铸态合金和固溶+时效热处理的轧制态合金综合力学性能均得到了显著提升，铸态 Al-Mg-Si-Cu 合金的抗拉强度、屈服强度和伸长率分别从 151、114 MPa 和 1.96%提升至 187、127 MPa 和 3.44%；轧制态 Al-Mg-Si-Cu 合金的抗拉强度、屈服强度和伸长率分别从 368、303 MPa 和 15.4%提升至 390、330 MPa 和 20.8%。The lightweighting of automobiles has imposed greater requirements on the mechanical properties of 6xxx series aluminium alloys. Thus, the development of 6xxx series aluminium alloy sheets for automotive bodies with high strength and toughness is urgently needed. The effects of adding 0.4 wt.% Sc on the microstructure and mechanical properties of Al-Mg-Si-Cu alloys were investigated by scanning electron microscopy (SEM), transmission electron microscopy (TEM), and universal mechanical testing machines. The results show that the addition of 0.4 wt.% Sc significantly refines the as-cast microstructure of the alloy, transforming coarse columnar grains into fine equiaxed grains and resulting in a more uniform microstructure. Under the influence of Sc, the morphology of the brittle β-AlFeSi phase in the as-cast alloy changes, with coarse lamellar β-AlFeSi transforming into fine needle-like structures. In the solution-treated and aged rolled alloy with 0.4 wt.% added Sc, the main precipitates include the secondary Al3Scphase, the Q′ phase, and the β″ phase. The synergistic effect of these three phases enhances the alloy's strength. The addition of 0.4 wt.% Sc significantly improves the overall mechanical properties of both the as-cast and solution-treated + aged rolled alloys. For the as-cast Al-Mg-Si-Cu alloy, the average tensile strength, yield strength, and elongation increase from 151, 114 MPa, and 1.96% to 187, 127 MPa, and 3.44%, respectively. For the rolled Al-Mg-Si Cu alloy after solution treatment and aging, the average tensile strength, yield strength, and elongation improved from 368, 303 MPa, and 15.4% to 390, 330 MPa, and 20.8%, respectively.