Incorporation of alumina particles with different shapes and sizes into molten aluminum alloy by melt stirring with ultrasonic vibration
Incorporation of alumina particles with different shapes and sizes into molten aluminum alloy by melt stirring with ultrasonic vibration
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DOI：
10.2320/matertrans1989.38.232
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发表时间：
1997-03-01
期刊：
影响因子：
--
通讯作者：
Mohri, N
中科院分区：
文献类型：
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作者：
Genma, Y;Tsunekawa, Y;Mohri, N
本文研究了超声振动搅拌条件下，颗粒形状和尺寸对Al-5 mass%Mg合金熔体中Al 2 O3颗粒的加入量的影响。提出了一个新的理论模型的颗粒转移到熔融金属处理不同形状的球形和块状颗粒合并的难度估计。在该模型中，粒子被假定为具有不同长轴和短轴的球体。其难易程度取决于界面张力引起的最大负加速度，随着最大负加速度的增大，Al 2 O3颗粒进入Al-Mg合金熔体的难度增大。将四种预热的Al 2 O3颗粒加入到熔融的Al-5mass%Mg合金表面，并在1023 K下在氮气气氛中用超声振动搅拌。掺入颗粒的体积分数与计算的最大加速度有关;也就是说，实验发现随着负最大加速度的增加而减少。根据该模型，超声振动使Al_2O_3颗粒与Al-Mg合金熔体的表观接触角从1.78 rad提高到0.87 rad。在超声振动成形的金属基复合材料中，气体缺陷消失了，而气体缺陷是熔体搅拌法制备的金属基复合材料中的一个严重问题。此外，由于团聚颗粒的分解，通过施加超声振动降低了用于熔体搅拌的旋转扭矩。因此，将超声振动应用于熔体搅拌是一种新型的MMC制备方法。
This paper presents the influence of particle shapes and sizes on the incorporation of Al2O3 particles into molten Al-5 mass%Mg alloy by melt stirring with ultrasonic vibration. A new theoretical model of particle transfer into molten metal dealing with different shapes is proposed to estimate the difficulty in incorporation of spherical and massive particles. In the model, the particles are assumed to be spheroids with different major and minor axes. The difficulty depends on the maximum acceleration which originates from the interfacial tension: the incorporation of Al2O3 particles into molten Al-Mg alloy becomes more difficult with the negative maximum acceleration increased. Four kinds of preheated Al2O3 particles were added to a molten Al-5 mass%Mg ahoy surface and stirred with ultrasonic vibration at 1023 K in a nitrogen atmosphere. The volume fraction of incorporated particles is related to the calculated maximum acceleration; that is, it is experimentally found to decrease as the negative maximum acceleration increased. according to the proposed model, the ultrasonic vibration makes the apparent contact angle of the Al2O3 particle and the molten Al-Mg ahoy improve from 1.78 to 0.87 rad. Gas defects, which are known to be a serious problem in metal matrix composites (MMC) produced by melt stirring, disappear in MMC samples formed with ultrasonic vibration. Moreover, the rotating torque for melt stirring decreases by applying ultrasonic vibration, because of the decomposition of agglomerate particles. Hence, the application of ultrasonic vibration to melt stirring is a novel candidate method of MMC production.