电磁连铸和微合金化对5356铝合金组织性能的影响  

Effects of EMC and Micro-alloying on Microstructure and Properties of 5356-Al Alloy

作　　者：邢清源[1] 孟令刚[1] 邓亮[1] 杨洪硕 甄立玲 刘红伟 房灿峰[1] 樊建勋 张兴国[1] 

机构地区：[1]大连理工大学,辽宁大连116024 [2]兵器科学研究院宁波分院,浙江宁波315000

出　　处：《稀有金属材料与工程》2016年第2期487-492,共6页Rare Metal Materials and Engineering

基　　金：国家自然科学基金(51375071);中央高校基本科研业务费专项资金(DOT12ZD205)

摘　　要：研究了不同电源功率、拉坯速率和冷却水量等参数以及微量Sc元素对5356铝合金组织和性能的影响。结果表明,在电源功率10 k W,拉坯速率8 cm/min,冷却水量1.7 m3/h的工艺条件下,5356铝合金具有最优的表面和内部质量以及综合力学性能,抗拉强度、伸长率分别可达310.0 MPa和16.3%,且铸锭表面无明显铸造缺陷,边部组织基本为等轴晶,心部组织呈破碎枝晶形态,第二相分布均匀。5356铝合金合理的均匀化处理工艺参数为440℃,30 h,空冷,均匀化处理后合金元素Mg的微观偏析基本消除,在晶界连续分布的Al8Mg5相明显回溶。微量的Sc元素显著提高5356铝合金的强度和塑性。实验证明,5356Al+0.4%Sc(质量分数)合金晶粒明显细化,第二相数量减少,抗拉强度和伸长率达330.0 MPa和29.0%,分别提高6.5%和77.9%。5356-Al alloy billets were prepared by an electromagnetic casting（EMC） technique and micro-alloying of Sc was also applied. The effects of power, casting rate, quantity of cooling water and Sc content on the microstructure and properties of 5356-Al alloy were investigated. The results show that the optimal EMC parameters of 5356-Al alloy are the power 10 kw, the casting speed 8 cm/min, and the quantity of cooling water is 1.7 m3/h, when the alloy has the best surface and internal quality and tensile properties. The tensile strength and elongation of the 5356-Al alloy can be up to 310.0 MPa and 16.3%, respectively, and the surface has no obvious casting defects. The microstructure of the edge is equiaxed crystals basically, while the center is broken dendrite crystals with a uniform distribution of the second phases. Besides, the homogenization heat-treatment of 5356-Al alloy has also been established： 440 ℃×30 h with the air cooling. After the homogenization heat-treatment, the micro-segregation of Mg has been eliminated basically and the phase Al8Mg5 which is distributed along the grain boundaries continuously dissolves. In addition, trace amount of Sc can improve the strength and plasticity of 5356-Al alloy. The experiment proves that 0.4 wt% Sc alloy can refine the grain size and reduce the number of the second phase of the 5356-Al alloy. At the same time, the tensile strength and elongation can be up to 330.0 MPa and 29.0%, which are increased by 6.5% and 77.9%, respectively.

关 键 词：5356铝合金 电磁连铸 显微组织 Sc元素 

分 类 号：TG146.21[一般工业技术—材料科学与工程]