论文标题
在不同条件下合金固化中平面不稳定性的标准：自由能的观点
The criterion of planar instability in alloy solidification under varying conditions: A viewpoint from free energy
论文作者
论文摘要
在合金固化中，热和溶质的传输过程导致界面的形态不稳定性，形成了不同的凝固结构模式，并确定了组件的机械性能。作为形态不稳定性的第一个可观察到的现象，平面的不稳定性影响了随后的阶段，值得深入研究。在本文中，研究了在不同条件下合金固化中的平面不稳定性。首先，平面不稳定性的动力学演变分别由理论模型和相位模型进行。其次，为代表固化的历史依赖性，在模拟中采用了不同的参数。然后讨论了在不同条件下平面不稳定性的标准。本文认为平面不稳定性的关键参数是界面和相应界面能量的过量自由能。最后，为了验证标准，进行了相位模型和理论模型之间的比较，显示出良好的一致性。此外，执行具有不同首选晶体学取向的凝固过程，证明了过量的自由能和界面能量对平面不稳定性的效果机制。影响平面不稳定性的界面能量的想法可以应用于研究界面不稳定性引起的其他模式。
In alloy solidification, the transport processes of heat and solute result in morphological instability of the interface, forming different patterns of solidification structure and determining the mechanical properties of components. As the first observable phenomenon of the morphological instabilities, the planar instability influences the subsequent stages significantly, deserving in-depth investigations. In this paper, the planar instability in alloy solidification under varying conditions is studied. Firstly, the dynamical evolution of the planar instability is performed by the theoretical model and phase-field model, respectively. Secondly, to represent the history-dependence of solidification, the varying parameters are adopted in the simulations. Then the criterion of the planar instability under the varying conditions is discussed. This paper considers the critical parameters of the planar instability are the excess free energy at the interface and corresponding interfacial energy. Finally, to validate the criterion, the comparisons between the phase-field model and theoretical model are carried out, showing good consistency. Moreover, solidification processes with different preferred crystallographic orientations are performed, demonstrating the effect mechanism of the excess free energy and interfacial energy on the planar instability. The idea of the interfacial energy influencing the planar instability could be applied to investigating other patterns induced by interfacial instability.
