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

几十年来，材料科学的进步一直推动着技术的进步。例如，在20世纪70年代的S和80年代的S，汽车中的铁部件被更轻的铝部件取代，导致了性能和燃油经济性的立竿见影的提高。最近，美国环境保护局和美国国务院。美国交通部要求汽车制造商在2025年之前减少温室气体排放，并将燃油经济性提高50%以上，否则将面临经济处罚。人们普遍认为，这种显著的改进可以通过车辆混合动力或车辆减重来实现。这两种方法都面临着挑战：1)杂交成本高，增加了车辆的重量；2)现有的轻质合金制造工艺正在接近技术极限，进一步进步的成本很高。在这项Engage赠款中，来自不列颠哥伦比亚大学和Nemak Canada的研究人员将探索一种创新的多工艺方法，以克服现有制造方法对超轻高强铝合金的限制。具体地说，先进的粉末冶金工艺(火花等离子烧结，SPS)将与传统的金属铸造工艺相结合，开发出新型的可铸造铝合金。利用SPS将纳米和微米级的陶瓷增强体与铝基粉末混合并烧结成圆盘状。随后在铸造过程中将烧结片加入液态铝合金中，导致熔体内铝基的溶解，随后陶瓷增强体在熔体内均匀释放。增强体将同时提高常温强度(通过细化晶粒和共晶变质)和蠕变抗力(通过晶界钉扎)。这一新的方法有望克服与当前液态铝合金处理方法相关的几个关键挑战(例如，颗粒固结、浮选或氧化)。实验工作将在UBC实验室以及位于安大略省的Nemak Canada Windsor铝厂进行。

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.