Development of new grain refiners for aluminum alloys for engine block applications

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For decades, technological advancements have been driven by the progress in materials science. For example,the substitution of iron components in automobiles with lighter aluminum components during the 1970's and80's resulted in an immediate performance and fuel economy enhancement. Recently, the EnvironmentalProtection Agency and the Dept. of Transportation in USA mandated automakers to decrease greenhouse gasemissions and improve fuel economy by over 50% by 2025, otherwise face economic penalties. It is generallyaccepted that such a drastic improvement is achievable either by vehicle hybridization, or by vehicle weightreduction. Both approaches face challenges: 1) Hybridization is costly and adds weight to vehicles, and 2)Existing manufacturing processes for lightweight alloys are approaching technological limits and furtheradvancements are costly.In this Engage grant, researchers from the University of British Columbia and Nemak Canada will explorean innovative multi-process approach to overcome the limits associated with existing manufacturing methodsfor ultralight high-strength aluminum (Al) alloys. Specifically, an advanced powder metallurgy process (SparkPlasma Sintering, SPS) will be combined with a traditional metalcasting process to develop novel castable Alalloys. Using SPS, nano- and micro-scale ceramic reinforcements will be blended with Al matrix powder andsintered into a disc. The sintered discs will be subsequently added to liquid Al alloys during casting, resultingin dissolution of the Al matrix within the melt, followed by a homogeneous release of the ceramicreinforcements inside of the melt. The reinforcements will serve to simultaneously enhance the roomtemperature strength (via grain refinement and the modification of eutectics) and creep resistance (via grainboundary pinning). This novel approach is anticipated to overcome several critical challenges (e.g., particlesettling, flotation or oxidation) associated with current treatment methods for liquid Al alloys. Experimentalwork will be carried out at UBC laboratories as well as at Nemak Canada Windsor Aluminum Plant, Ontario.