Interfacial Pattern Formation During Rapid Phase Transformations in a Binary System

合金的凝固通常发生在远离热平衡的条件下。这种快速凝固的过程需要特别关注的分段线性非平衡热力学的传统配方之外。所得到的固体的微观结构和性质在很大程度上取决于固化过程中的图案形成过程。将进行理论和实验工作。应考虑三个主要问题：（i）几个界面的传播及其相互作用，也涉及弹性力，（ii）界面在强非平衡条件下的快速传播，以及（iii）推进液-固界面前流体中的相分离。我们将采用分析和数值方法，包括边界积分和相场方法。理论建模的结果将进行比较，从过冷熔体的二元Co-Cu和Cu-Fe合金，这表明在过冷熔体中的亚稳两相区的凝固前沿动力学和微观结构的演变的测量结果。

Solidification of alloys often occurs under conditions far from thermal equilibrium. This process of rapid solidification requires special concern beyond the conventional formulations of piecewise linear non-equilibrium thermodynamics. The microstructures and thus the properties of the resulting solids are largely determined by the pattern-forming processes during solidification. Theoretical and experimental work will be performed. Three main topics shall be considered: (i) propagation of several interfaces and their interactions involving also elastic forces, (ii) fast propagation of interfaces under strong non-equilibrium conditions, and (iii) phase separation in the fluid ahead of an advancing liquid-solid interface. We will employ both analytical and numerical methods, including boundary-integral and phase-field methods. The results of theoretical modelling will be compared with results of measurements of the solidification front dynamics and the micro structure evolution from undercooled melts of binary Co-Cu and Cu-Fe alloys, which show a metastable two-phase region in the undercooled melt.