Preparation of Mg-Nd-Zn-(Zr) alloys semisolid slurry by electromagnetic stirring
Preparation of Mg-Nd-Zn-(Zr) alloys semisolid slurry by electromagnetic stirring
复制标题
电磁搅拌制备Mg-Nd-Zn-(Zr)合金半固态浆料
DOI：
10.1016/j.matdes.2016.01.131
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发表时间：
2016-04-05
影响因子：
8.4
通讯作者：
Ding, Wenjiang
中科院分区：
文献类型：
--
作者：
Chen, Yushi;Zhang, Liang;Ding, Wenjiang
研究了电磁搅拌（EMS）对Mg-Nd-Zn-（Zr）合金半固态浆料组织的影响。结果表明，所有的参数对浆料的微观结构有很大的影响。Mg-3 Nd-0.2Zn-0.4Zr（NZ 30 K）合金浆料经电磁搅拌处理后，初生α-Mg相由枝晶转变为玫瑰花、枝晶和球状3种形态，而Mg-3 Nd-0.2Zn-0.4Zr（NZ 30 K）合金浆料获得了细小球状的半固态组织。固体分数随搅拌时间的变化数据可以拟合成线性方程。外加电压和旋转频率的增加使初生a-Mg相先细化后粗化。NZ 30合金的最佳工艺参数为搅拌时间120-180 s，外加电压300-350 V，转速20 Hz左右; NZ 30 K合金的最佳工艺参数为搅拌时间30-180 s，外加电压350 V，转速20 Hz左右。NZ 30合金的平均粒度可由879 μ m左右细化到457 μ m左右。此外，还从热力学角度讨论了外加电压和旋转频率对过冷度和熔体温度的影响。(C)2016爱思唯尔有限公司版权所有
The effects of electromagnetic stirring (EMS) including stirring time, applied voltage and rotational frequency on the microstructure of semisolid slurries of the Mg-Nd-Zn-(Zr) alloys were investigated. The results indicate that all of the parameters have large effects on the microstructure of the slurries. After being treated by EMS, the morphology of primary alpha-Mg phases in the Mg-3Nd-0.2Zn (NZ30) alloy slurries evolves from dendrite to three types: rosette, dendrite, and spheroid, while a semisolid microstructure with small and spheroidal particles is obtained in the Mg-3Nd-0.2Zn-0.4Zr (NZ30K) alloy slurries. The data for solid fraction with stirring time can be fitted to linear equations. The increase of applied voltage and rotational frequency makes the primary a-Mg phases initially refined and then coarsened. The optimal processing parameters are stirring time 120-180 s, applied voltage 300-350 V, rotational frequency similar to 20 Hz for NZ30 alloy, and stirring time 30-180 s, applied voltage similar to 350 V, rotational frequency similar to 20 Hz for NZ30K alloy. The average particle size of NZ30 alloy can be refined from similar to 879 to similar to 457 mu m. Furthermore, the effects of applied voltage and rotational frequency on undercooling and melt temperature were also discussed on the basis of thermodynamic theory. (C) 2016 Elsevier Ltd. All rights reserved.