Rheological and atomistic characterization of liquid AL-SI alloys

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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.