Advanced Techniques for Analysis and Design in Materials Processing

超过90%的金属和合金加工经历凝固过程。这是一个复杂的过程/现象，出现在许多与铸造和表面处理相关的现代实验技术和工业技术中。不同凝固条件（如过冷或冷却速度）的变化使控制晶体结构的形态和尺寸成为可能，这实质上影响合金的物理和化学性能。特别是，合金的深度过冷低于平衡液相线和共晶导致快速凝固，并产生具有改进的机械，磁性和电学性能的材料。**铝镁钪合金（Al-Mg(Sc)）提供了巨大的机会，以提高强度比那些实现使用Al-Mg基合金。快速凝固过程中过冷使Sc在α基体中过饱和的能力为研究Sc对Al-Mg（Sc）合金性能改善的影响提供了新的途径。这项研究将包括理论和实验两部分。**实验粉末和喷雾形成的样品将产生使用脉冲雾化(IA) -单流体快速凝固技术。Al-Mg和Al-Mg（Sc）合金都会生成。固化后的样品将使用扫描和透射电子显微镜、x射线衍射、差示扫描量热法和显微硬度进行表征。此外，最先进的表征，如3d微和纳米层析成像和中子散射将进行。这些表征方法的目的是量化快速凝固样品中作为过冷函数的微偏析。利用逆微偏析模型，将建立初生相和共晶生长的枝晶生长速度与过冷温度（v vs δ at）之间的现象关系。这将与使用Al-Mg的经典LKT模型（固体尖锐界面生长的模型）获得的理论关系进行比较。**我们将提供一个基础，以了解导致铸造工艺的初始壳形成的凝固结构，如带状铸造、流变铸造和喷射沉积，其中冷却速率和热流通量与IA相似。我们也将首次提供一种新的方法来生成三元系统的v vs delta关系。提出的合金系统对于加拿大在生产和制造中发挥重要作用的汽车应用非常重要。两名研究生和五名本科生将在加拿大接受培训。

Over 90% of metals and alloys processed undergo a solidification process. This is a complex process/phenomenon arising in many modern experimental techniques and industrial technologies related to casting and surfaces processing. The variation of different conditions of solidification (such as undercooling or cooling rate) gives a possibility to control the morphology and size of crystal structure, which substantially influence physical and chemical properties of alloys. In particular, deep undercooling of alloys below equilibrium liquidus, and eutectics results in rapid solidification and yields materials with improved mechanical, magnetic and electrical properties.**Aluminum-magnesium-scandium alloys (Al-Mg(Sc)) offers great opportunities for increased strength over those achieved using Al-Mg based alloys. The ability to supersaturate Sc in the alpha matrix due to undercooling through rapid solidification offers a new approach to study the effect of Sc on the improved properties of Al-Mg(Sc) alloys. This research will have both theoretical and experimental components.**Experimentally powder and spray formed samples will be generated using Impulse Atomization (IA) - a single fluid rapid solidification technique. Both Al-Mg and Al-Mg(Sc) alloys will be generated. The solidified samples will be characterized using scanning and transmission electron microscopy and by X-Ray diffraction, differential scanning calorimetry,and microhardness. In addition, state of the art characterization such as 3D-micro and nano-tomography and Neutron Scattering will be carried out. The objective of these characterization methods is to quantify microsegregation in the rapidly solidified samples as a function of undercooling. Using an inverse microsegregation model, a phenomenological relationship between dendrite growth velocity and undercooling temperature (v vs deltaT) will be developed for both primary phase and eutectic growth. This will be compared with the theoretical relationship obtained using the classical LKT model for Al-Mg (a model of the growth of the sharp interface of the solid).**We will provide a basis for understanding the solidification structure of the initial shell formation resulting in casting processes such as strip casting, rheo-casting and spray deposition where cooling rates and heat fluxes are similar to IA. We will also for the first time provide a new method to generating v vs deltaT relationships for ternary systems. The proposed alloy systems are important for automotive applications where Canada plays a major role in production and manufacturing. Two graduate students and five undergraduates will be trained in Canada.