Spreading and solidification behavior of molten Si droplets impinging on substrates
Spreading and solidification behavior of molten Si droplets impinging on substrates
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DOI：
10.1016/j.actamat.2004.07.039
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发表时间：
2004-10
期刊：
影响因子：
9.4
通讯作者：
K. Nagashio;H. Murata;K. Kuribayashi
中科院分区：
文献类型：
--
作者：
K. Nagashio;H. Murata;K. Kuribayashi
利用红外成像系统直接观察了初始过冷度对硅在硅片上的铺展和凝固行为的影响。对于过热的液滴，熔体首先发生铺展，然后凝固。最后的飞溅形状是一个典型的光盘。对于初始过冷度较大的液滴，凝固速率快于熔体扩散速率，最终形成球形飞溅。结果表明，在大液滴（直径为1 mm）和低冲击速率（量级为1 mm/s）的可测量尺寸实验中，初始过冷度对最终形状有很大影响。此外，通过电子背散射图案分析，在整个淬火表面发现等轴晶粒。也就是说，微观结构的形成是成核控制的，因为平行于基板的生长受到抑制的熔体/基板的熔体变形所支配的时间依赖性的接触。
This paper focuses on an effect of initial undercoolings on the spreading and solidification behavior of Si dropped on a silicon wafer, which was directly observed through it by the infrared imaging system. For an overheated droplet, the melt spreading occurred first and solidified later. The final splat shape was a typical disc. On the other hand, for a droplet with large initial undercooling, the solidification took place at the faster rate than the melt spreading, which resulted in a spherical shape of final splat. It is indicated that the final shape is considerably affected by the initial undercooling in the measurable-scale experiment with large droplets (∼mm size) and low impingement rates (∼m/s order). Moreover, equiaxed grains were found throughout the quenched surface by an electron backscatter pattern analysis. That is, the microstructure formation was nucleation-controlled since the growth parallel to the substrate was suppressed by the time-dependent contact of melt/substrate governed by the melt deformation.