Rheological and atomistic characterization of liquid AL-SI alloys

最近的实验观察表明，与流行的假设相反，低共熔成分的液态Al-Si合金在低剪切速率下是非牛顿的。 从历史上看，存在着缺乏实验证据方面的表征液态铝合金的流变性能。 汽车制造商，如加拿大通用汽车公司（GM），以及他们的金属铸造供应链，必须深入了解铝合金的流变性能，以提高凝固微观结构的可预测性，缺陷形成，如孔隙度，以及开发新的和更先进的合金。 此外，过去没有尝试理解液态铝合金的晶体学。 对液态铝合金原子行为的深入理解将大大提高这些合金凝固过程中微观结构和物理性能的可预测性。 目前，在Ecole Polytechnic，QC正在开发模型来预测铝合金的热力学和物理性能。 本计画将进行实验来验证这些模型。 该项目的交付成果将包括通过流变实验和中子及X射线衍射技术量化特定铝合金的流变性能以及合金元素对这些性能的影响。 此外，该项目旨在了解液态铝合金流变学变化背后的基本机制，并通过透彻了解凝固过程中的液体结构来表征某些基本物理特性。 这种知识基础是缺乏我们目前的铝合金系统的理解。该项目将是麦克马斯特大学机械工程系、蒙特利尔理工学院化学工程系和通用汽车研究人员之间的合作研发工作。

Recent experimental observations have shown that, contrary to popular assumptions, liquid Al-Si alloys of eutectic composition are non-Newtonian at low shear rate regimes.  Historically, there exists a lack of experimental evidence with respect to the characterization of rheological properties of liquid aluminium alloys.  It is imperative that automotive manufacturers, such as General Motors of Canada (GM), as well as their metal casting supply chain, have an in-depth understanding of the rheological properties of aluminium alloys to improve the predictability of solidification microstructure, defect formation, such as porosity, and development of novel and more advanced alloys.  Additionally, there has been no attempt in the past to understand the crystallography of liquid aluminium alloys.  An in-depth understanding of the atomistic behaviour of liquid Al alloys will greatly enhance predictability of microstructure and physical properties during solidification of these alloys.  Presently, models are being developed at Ecole Polytechnic, QC to predict thermodynamic and physical properties of Al alloys.  Experiments will be carried out in this project to verify and validate these models.  The deliverables of this project will include the quantification of rheological properties of specific aluminium alloys and the effect of alloying elements on these properties via rheological experiments and neutron and X-ray diffraction techniques.  Furthermore, the project aims to understand the fundamental mechanism behind the change in rheology of liquid Al alloys and characterize certain fundamental physical properties via thorough understanding of the liquid structure during solidification.  This knowledge-base is lacking in our present understanding of Al alloy systems. The project will be a collaborative R&D effort among the faculties at  Mechanical Engineering at McMaster University, ON, Chemical Engineering at École Polytechnique de Montréal, QC, and GM researchers.