金属熔体本征过冷度与熔化熵的耦合关系

利用气动悬浮和熔融玻璃净化法对液态纯铁的过冷能力进行研究, 分别获得了340 和281K 的最大过冷度, 表明在气动悬浮无容器凝固条件下液态纯铁的形核更接近于均质形核.根据经典形核理论和Spaepen 界面能公式, 建立了金属熔体本征过冷度(即均质形核对应的过冷度)与熔化熵之间的耦合关系方程. 并根据该方程预测了一系列金属熔体的本征过冷度, 对比结果表明预测值与实验值具有较好的一致性.

Correlations between molar fusion entropy and the intrinsic undercoolability of liquid metals

High undercoolings up to 340 K and 281 K for pure liquid iron are achieved using aerodynamic containerless levitation and a glass fluxing method, respectively. This implies that the nucleation of liquid iron under aerodynamic containerless solidification condition is closer to homogeneous nucleation. Based on the classical nucleation theory and Spaepen’s expression for solid/liquid interfacial energy, a correlation equation between intrinsic undercooling, namely, the undercooling corresponding to homogeneous nucleation and molar entropy is derived. From this equation, intrinsic undercoolings for a series of liquid metals can be predicted. Good agreement exists between the predicted and experimental results.