Steady and oscillatory cellular morphologies in rapid solidification.
Steady and oscillatory cellular morphologies in rapid solidification.
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快速凝固中的稳定和振荡细胞形态。
DOI：
10.1103/physrevb.34.1746
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发表时间：
1986
期刊：
影响因子：
--
通讯作者：
L. Ungar
中科院分区：
文献类型：
--
作者：
Francis X. Kelly;L. Ungar
计算了形态不稳定的快速凝固金属和半导体的振幅胞状凝固前沿。采用二维定向凝固模型，考虑了掺杂剂的非平衡偏析。温度，浓度，和熔体-固体界面形状的温度，浓度，和熔体-固体界面的近似值与计算机实现的微扰技术和一个完全隐式的时间积分方案一起使用，以分析凝固速率和掺杂剂浓度的熔体-固体界面形态的依赖关系。发现了胞状界面之间具有不同时空振荡频率的过渡序列，观察到稳定的胞状熔体-固体界面族的时间周期振荡，表现为既脱离平面族又脱离振荡族的Hopf分叉。利用快速凝固掺锑硅的计算，阐明了非平衡掺杂偏析在驱动振荡界面形态中的作用。
Finite-amplitude cellular solidification fronts are calculated for morphologically unstable rapidly solidifying metals and semiconductors. A two-dimensional directional solidification model is used which accounts for nonequilibrium segregation of dopant. Finite-element approximations of temperature, concentration, and melt-solid interface shape are used in conjunction with computer-implemented perturbation techniques and a fully implicit time integration scheme to analyze the dependence of melt-solid interface morphology on solidification rate and dopant concentration. A sequence of transitions between cellular interfaces with different spatial and temporal oscillation frequencies is found. Stable time-periodically oscillating families of cellular melt-solid interfaces are observed as Hopf bifurcations both off of the planar family and off of oscillatory families. The role of nonequilibrium dopant segregation in driving oscillatory interface morphologies is elucidated with use of calculations for rapidly solidified antimony-doped silicon.