Grant: Discovery Grants Program - Individual

Canada's automotive industry the biggest contributor to manufacturing GDP and largest manufacturing employer is facing mounting pressures in several key areas including energy, emissions, and safety. Much of the materials science efforts in the transport industry is driven by the stringent regulation of fuel economy and climate-warming emissions. Lightweighting is a key strategy to address these challenges, since a 10% weight reduction results in a 6~8% fuel-efficiency gain. It has recently been portrayed as the ""storm"" of lightweighting a revolution in materials, processes, and business models. This, along with materials designed for improved fatigue, creep, impact, or corrosion resistance, has been identified as one of six areas critical to solving national and global grand challenges. The research and development of lightweight materials, which are predicted to reach a global market of US$186 billion by 2020, have become one of the hottest areas in materials science and engineering. Magnesium is the lightest structural metal and is regarded as an ideal lightweight material to replace heavier metals. However, there are big hurdles to its wide applications, including low formability and strength, fatigue and reliability, corrosion resistance, welding and joining. Recent ground-breaking developments in magnesium-lithium alloys called ""stainless magnesium"" and magnesium nanocomposites pave the way for lightweight structural applications. The questions remain how these new alloys behave during cyclic deformation, if twinning and detwinning occur, and if the anisotropy and tension-compression yield asymmetry still exist. The proposed research is aimed to address these key questions and obstacles building upon the applicant's pioneering and extensive research experience and knowledge in this area, and develop a fundamental understanding of deformation and fatigue of magnesium alloys and other lightweight materials. Specifically, the following topics will be examined: i) the underlying cyclic deformation and twinning-detwinning mechanisms in new magnesium alloys will be elucidated and modeled, ii) the texture and residual stresses will be evaluated and analyzed using a unique high-temperature X-ray diffractometer which permits in-situ measurements as a function of temperature, iii) the deformation and fatigue resistance of dissimilar welded joints based on the ""multi-material"" lightweighting strategies will be examined, and iv) new processing approaches and models will be developed to weaken textures and anisotropy. These projects will improve fundamental understanding of deformation behavior, open the door to the development of next-generation high-performance lightweight materials, contribute to achieving the ultimate goal of constructing lightweight vehicles, protecting our environment and enhancing Canadian competitiveness in the global market.