Gas Atomization of Amorphous Aluminum: Part I. Thermal Behavior Calculations
Gas Atomization of Amorphous Aluminum: Part I. Thermal Behavior Calculations
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DOI：
10.1007/s11663-009-9276-5
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发表时间：
2009-08
期刊：
影响因子：
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通讯作者：
B. Zheng;Yaojun Lin;Yizhang Zhou;E. Lavernia
中科院分区：
文献类型：
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作者：
B. Zheng;Yaojun Lin;Yizhang Zhou;E. Lavernia
本文采用数值模拟的方法研究了气体雾化铝基非晶粉末的热历史和冷却速率。建模模拟是基于牛顿冷却与强制对流的假设，以及能量平衡，其中涉及气体动力学，液滴动力学，以及气体和液滴之间的传热。为了使问题易于处理，相变，晶体成核和生长不考虑在铝液滴的凝固的分析，相反，能量平衡的方法制定和使用。利用数值计算结果和相关分析，对铝基非晶粉末气体雾化过程中的工艺参数进行了优化。结果表明，液滴的冷却速率随粉末粒度的减小而增大，当粉末粒度小于20μm时，液滴的冷却速率可达105 K/s以上。气体成分对冷却速率的影响比气体压力大，100%He的冷却效果最好。结果还表明，冷却速率随熔体温度的升高而增大。
In this article, the thermal history and cooling rate experienced by gas-atomized Al-based amorphous powders were studied via numerical simulations. Modeling simulations were based on the assumption of Newtonian cooling with forced convection, as well as an energy balance, which involves gas dynamics, droplet dynamics, and heat transfer between gas and droplet. To render the problem tractable, phase transformations, crystal nucleation, and growth were not taken into account in the analysis of the solidification of Al droplets; instead, an energy balance approach was formulated and used. The numerical results and associated analysis were used to optimize processing parameters during gas atomization of Al-based amorphous powder. The results showed that the cooling rate of droplets increases with decreasing powder size and can reach in excess of 105K/s for powder <20μm in diameter. Gas composition has a more significant influence on cooling rate than gas pressure, and 100 pct He has the highest cooling effect. The results also showed that the cooling rate increases with increasing melt superheat temperature.