Sc含量对Al-7Mg合金铸轧板显微组织与性能的影响  

Effect of Scandium content on microstructure and properties of Al-7Mg alloy cast-rolled sheets

作　　者：王重懿 徐潘宁 付金禹 李勇[3] 许光明 WANG Zhongyi;XU Panning;FU Jinyu;LI Yong;XU Guangming(Key Laboratory of Electromagnetic Processing of Materials(Ministry of Education),Northeastern University,Shenyang 110819,China;Northeast Light Alloy Co.,Ltd.,Harbin 150060,China;State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China)

机构地区：[1]东北大学材料电磁过程研究教育部重点实验室,辽宁沈阳110819 [2]东北轻合金有限责任公司,黑龙江哈尔滨533402 [3]东北大学轧制技术及连轧自动化国家重点实验室,辽宁沈阳110819

出　　处：《轻合金加工技术》2024年第8期28-36,共9页Light Alloy Fabrication Technology

摘　　要：主要采用金相显微镜(OM)、扫描电镜(SEM)、差示扫描量热法(DSC)和拉伸试验等检测手段,研究了不同含量的Sc对Al-7Mg合金板材的微观组织和力学性能的影响。试验结果表明:Sc对于减轻由双辊铸轧快速凝固及高镁含量产生的中心偏析带具有显著作用,增加Sc含量后,双辊铸轧板的晶粒尺寸逐渐减小,二次枝晶臂间距最小可减小到9.92μm;各元素的偏析度减小,偏析基本消除;合金中的非平衡共晶相的数量也呈现明显的下降趋势。同时,w(Sc)由0.1%增加到0.2%使得Al-7Mg合金的屈服强度提高了57 MPa,抗拉强度提高了35 MPa,伸长率提高了4.3%。Sc的加入使得凝固过程中的形核率提高,枝晶的生长受到抑制,同时Sc细化晶粒效果显著,并使偏析减轻,明显提高了合金的力学性能。The effects of different contents of scandium on the microstructure and mechanical properties of Al-7Mg alloy sheets were studied by means of metallographic microscope(OM), scanning electron microscope(SEM), differential scanning calorimetry(DSC) and tensile test. The experimental results show that scandium plays a significant role in reducing the central segregation zone caused by rapid solidification and high magnesium content in twin-roll casting. After increasing the content of scandium, the grain size of twin-roll casted sheet decreases gradually, and the secondary dendrite arm spacing can be reduced to 9.92 μm minimum. The segregation degree of each element decreases and the segregation is basically eliminated, and the number of non-equilibrium eutectic phases in the alloy also shows an obvious downward trend. At the same time, with the scandium content increasing from 0.1wt.% to 0.2wt.%, the yield strength, tensile strength and elongation of Al-7Mg alloy increase by 57 MPa, 35 MPa and 4.3%, respectively.The addition of scandium element increases the nucleation rate during solidification and restrains the growth of dendrites. At the same time, scandium element improves grain refinement, reduces segregation, and obviously improves the mechanical properties of the alloy.

关 键 词：双辊铸轧 高镁铝合金 偏析缺陷 组织与性能 

分 类 号：TG146.21[一般工业技术—材料科学与工程]