Towards Stainless Magnesium

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Growing CO2 emissions from the transportation sector contribute 25% of Canada's total greenhouse gas (GHG) emissions; the government has a target for reducing GHGs by 45-65% by 2050. Ten percent saving in vehicle weight leads to 6-8% fuel economy improvement, which translates (during the life time of a car) to 17-20 kg reduced emissions of CO2, per kg of vehicle weight reduced. Lightweight magnesium (Mg) with density 2/3 of aluminum (Al) and 1/4 of steel offers unique advantages for fuel efficiency and reduced emissions in targeted automotive applications. A key shortcoming of Mg in this effort is its susceptibility to corrosion, which limits its wide application. Recently, certain alloying elements such as arsenic (As) added at low levels were found to retard the chemical reactions leading to the corrosion of Mg [1]. FCA Canada Inc. is interested in developing a corrosion resistant Mg alloy ("stainless Mg") to widen the use of lightweight structural components in its vehicles. In this project, we will develop corrosion resistant automotive Mg alloys using trace element additions of As, bismuth (Bi), antimony (Sb) and/or cerium (Ce) to Mg-Al based alloys commonly used in automotive applications. In the proposed project, the objectives are: (i) to design Mg-Al-As, Mg-Al-Bi and Mg-Al-Sb based alloys using thermodynamic calculations (FactSage); (ii) to characterize the microstructures /phase selection of selected alloy compositions to validate the thermodynamic calculations; and (iii) to conduct a preliminary evaluation of the mechanical properties of selected compositions. The successful outcome of this project will pave the path to long term collaboration with FCA to develop corrosion resistant Mg alloys, to innovate, and to secure higher market share. Downstream Tier I/Tier II suppliers in Canada will also benefit from the positive outcome of this project. HQP trained in this project will have key expertise in the lightweight transport applications and will help keep these key industries in Canada. They will be positioned to advance the magnesium transformation industry in the country and have transferable skills in electron microscopy, x-ray diffraction, mechanical testing and computational materials engineering.