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实时观测了切向流动作用下SCN-0.2%Salol透明合金的定向胞晶生长过程,研究了切向流动作用对胞晶间距调整的作用机理.实验发现,切向流动使得胞晶阵列发生顺流偏转,并且稳态平均间距随流速的增高而减小.分析表明,这主要是由于流动作用导致胞端失稳波长减小而引起.施加切向流动使得胞晶间距的调整过程中的分裂机理多样化.顶端分裂由均匀分岔转变为多枝分岔和不对称分岔;同时,胞晶迎流侧容易产生分枝,且分枝生长方向在流动作用下转变为与胞晶主干方向相同.胞晶的淘汰机理由静态条件下的弱势生长胞晶被相邻两侧胞晶淘汰转变为切向流动作用下的上游生长占优势胞晶淘汰下游弱势胞晶.
The directional cell growth of SCN-0.2% Salol transparent alloy under tangential flow was observed in real time, and the mechanism of tangential flow on the adjustment of cell spacing was also studied. The results show that tangential flow makes the cell array co-current Deflection, and the steady-state average spacing decreases with the increase of the flow rate.The analysis shows that this is mainly due to the decrease of the cell-end instability wavelength caused by the flow.The application of tangential flow makes the splitting mechanism Diversification.The apical division changes from uniform bifurcation to multi-branch bifurcation and asymmetric bifurcation.At the same time, the branchlets are easy to produce branches on the flow-in side, and the branching growth direction is changed to the same direction The elimination mechanism of the cell is that the weakly growing cell under the static condition is transformed into the cell under the influence of tangential flow and the dominant cell under the influence of tangential flow to eliminate the weak cell.