摘要
针对普通半连铸大规格铝合金铸锭通常存在的晶粒粗大、组织不均匀以及由此导致的强度较低等问题,本研究在普通电磁搅拌和环缝式电磁搅拌的基础上,提出了一种新型熔体处理方法—内部电磁搅拌,并将此方法应用于2219铝合金半连铸试验。通过与普通半连铸对比,探究内部电磁搅拌对大规格铝合金铸锭组织及性能的影响,以期为半连铸更大规格的铝合金铸锭提供参考与借鉴。结果表明,相较于普通半连铸,内部电磁搅拌半连铸2219铝合金铸锭的晶粒更加细小,组织更加均匀,从边部到心部的晶粒直径均在127～151μm范围之内;第二相的尺寸减小,分布均匀且数量显著减少;铸锭的性能大幅提高,在延伸率和断面收缩率提高的情况下,平均抗拉强度提高了11%,达到389 MPa,平均屈服强度提高了10%,达到286 MPa,平均布氏硬度从HB 117.8提高到HB 137.8,增幅达17%,且铸锭的性能随着位置的变化波动较小;断口扫描发现铸锭中的疏松缺陷大幅减少。
Severe problems such as coarse grain, inhomogeneous microstructure and correspondingly lower strength usually exist in the large-sized aluminum alloy billet prepared by normal direct chill casting. According to those problems, a new melt treatment technique named internal electromagnetic stirring(I-EMS) was put forward, which was based on the normal electromagnetic stirring and annular electromagnetic stirring. The internal electromagnetic stirring was utilized for 2219 aluminum alloy direct chill casting experiment to explore its effects on microstructure and mechanical properties of billet by comparing with the normal direct chill casting, in order to provide references and suggestions for the larger-sized billet. The results showed that after melt treatment by internal electromagnetic stirring, the grains were finer and the microstructures were more uniform, of which the grain diameter were in the range of 127~151 μm. Moreover, the size and number of second phase decreased as well as it distributed homogeneously. Accordingly, its average tensile strength and yield strength increased by 11% and 10%, reaching to 389 and 286 MPa, respectively. The average Brignell hardness also increased by 17%, improving from HB 117.8 to HB 137.8. Furthermore, its properties fluctuated little with the position change while its porosities decreased significantly.
作者
邱阳
张志峰
高明伟
李豹
陈春生
Qiu Yang;Zhang Zhifeng;Gao Mingwei;Li Bao;Chen Chunsheng(National Engineering&Technology Research Center for Nonferrous Metal Matrix Composite,General Research Institute for Nonferrous Metals,Beijing 100088,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2019年第2期122-127,共6页
Chinese Journal of Rare Metals
基金
国家国际科技合作计划(2015DFA51230)资助
关键词
内部电磁搅拌
2219铝合金
组织及第二相
力学性能
断口形貌
internal electromagnetic stirring
2219 aluminum alloy
microstructure and second phase
mechanical properties
fracture morphology
