Andilab Bernoulli, Emadi Payam, Ravindran Comondore
Centre for Near-Net-Shape Processing of Materials, Toronto Metropolitan University, Toronto, ON M5B 2K3, Canada.
Materials (Basel). 2022 Oct 17;15(20):7232. doi: 10.3390/ma15207232.
Advanced metallurgical processing techniques are required to produce aluminum matrix composites due to the tendency of the reinforcement particles to agglomerate. In this study, graphene nano-platelet reinforcement particles were effectively incorporated into an automotive A319 aluminum alloy matrix using a liquid metallurgical route. Due to its low density, it is a highly difficult task to produce an aluminum matrix composite reinforced with graphene. Hence, this study explored a novel approach to prevent particle floating to the melt surface and agglomeration. This was achieved via a hybrid semi-solid stirring of A319, followed by ultrasonic treatment of the liquid melt using a sonication probe. The microstructure and graphene particles were characterized using optical microscopy and scanning electron microscopy. Furthermore, the interfacial products produced with the incorporation of graphene in liquid aluminum were analyzed with X-ray diffraction. The tensile test results exhibited 10, 11 and 32% improvements in ultimate tensile strength, yield strength, and ductility of A319 reinforced with 0.05 wt.% addition of graphene. Analysis of strengthening models demonstrated primary contribution from Hall-Petch followed by CTE mismatch and load bearing mechanism. The results from this research enable the potential for using cost-effective, efficient and simple liquid metallurgy methods to produce aluminum reinforced graphene composites with improved mechanical properties.
由于增强颗粒有团聚的倾向，所以需要先进的冶金加工技术来生产铝基复合材料。在本研究中，采用液态冶金路线将石墨烯纳米片增强颗粒有效地加入到汽车用A319铝合金基体中。由于其低密度，生产以石墨烯增强的铝基复合材料是一项极具挑战性的任务。因此，本研究探索了一种防止颗粒漂浮到熔体表面和团聚的新方法。这是通过对A319进行混合半固态搅拌，然后使用超声探头对液态熔体进行超声处理来实现的。利用光学显微镜和扫描电子显微镜对微观结构和石墨烯颗粒进行了表征。此外，还用X射线衍射分析了在液态铝中加入石墨烯后产生的界面产物。拉伸试验结果表明，添加0.05 wt.%石墨烯增强的A319的极限抗拉强度、屈服强度和延展性分别提高了10%、11%和32%。强化模型分析表明，主要贡献来自霍尔 - 佩奇效应，其次是热膨胀系数失配和承载机制。本研究结果表明，利用经济高效且简单的液态冶金方法生产具有改善机械性能的铝增强石墨烯复合材料具有潜力。
