Predicting the mechanical properties of foundry aluminium alloys for high temperature applications

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In June 2012, the International Agency for Research on Cancer (IARC), which is part of the World Health Organization (WHO), classified diesel engine exhaust as carcinogenic to humans. This was based on sufficient evidence that exposure is associated with an increased risk for lung cancer. In Europe, more than 50% of the cars run on Diesel. In France, it is about 80%. According to Health Canada, in 2007, the transportation sector emissions represented about 27% of Canada's total emissions inventory. Car manufacturers have been coasting on the success of their highly profitable Diesel engines for more than 30 years. Surprisingly, very few laws were controlling the effects that the heavy, thick, black smoke was having on peoples' health. Extreme depollution of the fume (NOx traps, particulate filters, etc...) appears to not be enough to significantly control its' negative effects. However, the massive downsizing of the engines is a step forward in significantly decreasing the pollution of Diesel engines. Nonetheless, such a challenge can't be reached without an innovative thermal treatment, and a complete understanding of its impact on the microstructure of the aluminum alloy. This project sets out to take on this challenge, using a numerical multiscale approach coupled with strong experimental processes. In other words, it aims to accurately understand the benefits and the negatives of the thermal treatment, particularly the quenching process that is used to manufacture the head cylinder. The research involves the concomitant modeling of nucleation-growth-coarsening of Al2Cu particles. The interaction of the dislocations with the precipitates is included in the model and will help to determine the yield stress of the aluminum alloy. This model will then be implemented into a finite element software in order to perform computation on industrial meshes. The results will be validated by an experimental approach involving, amongst other things, microscopic analysis and mechanical testing. The project is led by an international team, involving Université Laval, Université du Québec à Chicoutimi, Centre de Métallurgie du Québec, Rio Tinto Alcan and Montupet S.A.