Transactions of Nonferrous Metals Society of China The Chinese Journal of Nonferrous Metals

您目前所在的位置:首页 - 期刊简介 - 详细页面

中国有色金属学报

ZHONGGUO YOUSEJINSHU XUEBAO

第27卷    第3期    总第216期    2017年3月

[PDF全文下载]        [Flash在线阅读]

    

文章编号:1004-0609(2017)-03-0468-09
AZ80镁合金低压脉冲磁场半连续铸造过程的数值模拟和实验研究
冀焕明,罗天骄,杨院生

(中国科学院 金属研究所,沈阳 110016)

摘 要: 采用有限元方法对AZ80镁合金低压脉冲磁场半连续铸造过程的电磁场、流场和温度场进行数值模拟,对铸锭的组织进行观察和分析,并与普通半连续铸造铸锭晶粒组织进行对比。模拟结果表明:在低压脉冲磁场半连续铸造过程中,结晶器中的熔体受脉冲电磁力作用产生强迫对流和电磁振荡,使得熔体的径向温度梯度有所降低。组织观察结果显示,与普通半连续铸锭相比,低压脉冲磁场半连续铸锭晶粒明显细化,枝晶尖端发生钝化。在低压脉冲磁场半连续铸造凝固过程中,结晶器壁附近形核的临界形核半径和临界形核功有所降低,同时脉冲磁场形成的熔体对流使结晶器壁处形成的晶核随着对流扩散到熔池内部,使形核率增加,另外脉冲磁场能够通过尖端钝化的方式抑制晶粒的生长,从而造成低压脉冲磁场铸锭的晶粒细化。

 

关键字: 镁合金;低压脉冲磁场;半连续铸造;数值模拟;晶粒细化

Numerical simulation and experimental research of low voltage pulsed magnetic field DC casting of AZ80 magnesium alloy
JI Huan-ming, LUO Tian-jiao, YANG Yuan-sheng

Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China

Abstract:The electromagnetic field, flow field and temperature field during the low voltage pulsed magnetic field direct chill casting of AZ80 magnesium alloy were simulated with finite element method, and the microstructure of the billet was observed by comparing those of billet by conventional direct chill (DC) casting process. The simulation results indicate that, during the low voltage pulsed magnetic field DC casting process, affected by electromagnetic force, forced convection and velocity vibration generate in the melt, leading to the reduced temperature grade of melt along the radial direction. The results show that the grains of the billet cast with low voltage pulsed magnetic are significantly refined and the tip of dendrite is rounded, compared with those of the conventional one. During the low voltage pulsed magnetic field DC casting process, the critical nucleation radius and critical nucleation energy near the crystallizer decrease, at the same time, the nuclei formed ahead the inner wall of crystallizer can be dispersed into the centre of the molten pool with the convection that caused by the pulsed magnetic field, which causes the increased nucleation rate. In addition, the growth of dendrite tip is inhibited by the passivation effect of the pulsed magnetic field, which leads to the grain refinement in the low voltage pulsed magnetic field direct chill casting billet.

 

Key words: magnesium alloy; low voltage pulsed magnetic field; direct chill casting; numerical simulation; grain refinement

ISSN 1004-0609
CN 43-1238/TG
CODEN: ZYJXFK

ISSN 1003-6326
CN 43-1239/TG
CODEN: TNMCEW

主管:中国科学技术协会 主办:中国有色金属学会 承办:中南大学
湘ICP备09001153号 版权所有:《中国有色金属学报》编辑部
------------------------------------------------------------------------------------------
地 址:湖南省长沙市岳麓山中南大学内 邮编:410083
电 话:0731-88876765,88877197,88830410   传真:0731-88877197   电子邮箱:f_ysxb@163.com