论文标题
从扩散控制方向固化上的耗散动力学的观点
A viewpoint from dissipative dynamics on diffusion-controlled directional solidification
论文作者
论文摘要
现有的凝固动力学理论分析缺乏整个系统中历史相关性和运输过程的见解。通过相位模型，本文研究了整个方向固化过程中整个域的演变。首先，获得了特征参数的演变，包括在界面和尖端速度之前的溶质浓度，证明了凝固的耗散特征。其次，通过调整扩散系数DL，可以改变界面处的耗散。在不同的DL中，研究了定向凝固过程中不同的阶段，包括平面生长和不稳定性，树突生长和稳态生长。结果表明溶质扩散在合金固化中的重要作用。从整个域的角度来看，较小的DL对应于较高程度的耗散程度，在凝固过程中形成更多的接口。此外，尖端曲率和速度的竞争影响也是由于原子摩擦而导致的耗散。
The existing theoretical analyses of solidification dynamics lack the insights of historical relevance and transport processes in the whole system. Through the phase-field model, this paper investigates the evolution in the whole domain during entire directional solidification. First, the evolution of characteristic parameters is obtained, including the solute concentration ahead of interface and tip velocity, demonstrating the dissipative features of solidification. Second, by adjusting the diffusion coefficient DL, the dissipation at the interface can be altered. With different DL, different stages during directional solidification are investigated, including planar growth and instability, dendrite growth, and steady-state growth. The results indicate the important role of solute diffusion in alloy solidification. From the viewpoint of the whole domain, smaller DL corresponds to a higher degree of dissipation, forming more interfaces during solidification. Moreover, the competitive influences of tip curvature and velocity are also because of the dissipation, resulting from the friction of atoms.
