Heterogeneous Nucleation During Solidification of Undercooled Liquid Metals

9308148 PEREPEZKO这项研究探索了过冷液态金属合金中非均相形核的动力学。动力学评价方法遵循两个方向：实验测量和计算机模拟。锡-锑合金体系的液滴样品在稳定的载液中乳化并过冷。用量热法跟踪过冷过程中的形核事件，并通过定量图像分析确定液滴的尺寸分布和体积相分数。用扫描电子显微镜、能谱仪和X射线衍射仪对熔滴的微观结构和成分进行了分析，得到了动力学和热力学结果。计算机模拟采用动力学蒙特卡罗方法，研究了作为时间函数的临界核尺寸、形状因子和运动边界上的形核。%成核是一种广泛存在的物理现象，在金属、陶瓷、有机、生物和水体系中起着重要的作用。这项适用于这些系统的研究应该会产生新的见解。***

9308148 Perepezko This research explores kinetics of heterogeneous nucleation in undercooled liquid metal alloys. The approach to the kinetics evaluation follows two directions: experimental measurement and computer simulation. Droplet samples from the tin-antimony alloy system are emulsified in a stable carrier fluid and undercooled. Nucleation events during undercooling are followed by calorimetry and the droplet size distribution and volume phase fraction determined by quantitative image analysis. Kinetic and thermodynamic results are related to the microstructure and composition of the solidified droplets by employing scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Computer simulation employs the Kinetic Monte Carlo method and addresses critical nucleus size, shape factors, and nucleation at moving boundaries as a function of time. %%% Nucleation is a physical phenomena of broad occurrence, playing an important role in metallic, ceramic, organic, biological, and aqueous systems. New insights should result from this research applicable to these systems. ***