重力对流作用下枝晶生长的形貌研究

Effects of Gravity Convection on Dendritic Growth Morphology During Solidification

以透明模型合金丁二腈-5%乙醇作为试验对象,利用自行研制的生长室和生长观察系统,详细考查了垂直于生长界面的重力对流作用下,丁二腈-5%乙醇模拟合金枝晶形貌生长的演化过程。研究表明,随着生长速度的增大,重力对流作用下枝晶一次间距相对于无重力对流情况时增大,尖端半径相对于无重力对流时减小;重力对流使得枝晶迎流侧二次臂生长较快,较为发达;流场产生的Stokes力和重力的共同作用最终造成了枝晶尖端形态的顺流偏转。

The effects of gravity convection perpendicular to growing surface on dendritic morphology growth of model alloy SCN-5% ethanol have been observed by a self-developed experimental apparatus, which has a growth room and an observation system. The results indicate that, compared with those in condition of the absence of gravity convection, the primary arm spacing can be increased and tip radius can be reduced with the increase of growth speed. Gravity convection can result in the rapid growth and more development of the second arm spacing at facing-flow side. The down-stream alternation of dendritic tip growth is attributed to the co-action of the Stokes force and gravity in the flow field.