Collaborative Research: Friction Stir Processing of Cast Metal Matrix Nanocomposites

将纳米粒子掺入轻金属中，形成金属基纳米复合材料，可以显着增强性能，从而对汽车、航空航天和其他需要轻质结构部件以实现高能源效率的行业产生巨大影响，这也意味着减少空气污染。 然而，在金属凝固过程中很难实现纳米颗粒的良好分散和捕获。将纳米颗粒有效地掺入高温金属熔体中也提出了一个严重的问题。搅拌摩擦加工可以作为在相对较低的温度下通过半固态加工制造的轻质金属基纳米复合材料中分散纳米颗粒的有力工具。该奖项支持基础研究，以提供创建简单、新颖且可扩展的制造技术所需的知识，从而推动金属基纳米复合材料走向广泛应用。该研究将吸引、保留和吸引来自代表性不足群体的学生。 K-12 学生/教师和行业合作伙伴将接触到新技术。将开发跨学科课程材料来培训研究生和本科生。该合作项目的目标是（1）通过对加工过程中纳米颗粒运动和分散在颗粒内部的系统实验研究，显着促进摩擦搅拌加工如何与轻质金属基纳米复合材料中的纳米颗粒相互作用的基本理解，（2）通过研究纳米颗粒尺寸和形态、纳米颗粒负载以及加工参数对微/纳米结构的影响，了解加工-微观结构-性能关系。纳米复合材料的演变和由此产生的机械性能。用于实验研究的金属基纳米复合材料将通过半固态铸造和搅拌摩擦加工相结合的方式制造，以在相对较低的温度下有效地结合半固态纳米粒子，并分散纳米粒子并细化固态微观结构，以获得优异的性能。通过微/纳米材料分析工具，本研究将表征半固态合金中的微/纳米结构、纳米颗粒的掺入和分布，以及金属基纳米复合材料中搅拌摩擦加工的纳米颗粒分散情况。将进行拉伸和硬度（宏观、微观和纳米）测试，以表征搅拌摩擦加工前后纳米复合材料的机械性能。

Incorporation of nanoparticles into light metals, forming metal matrix nanocomposites, can lead to significantly enhanced properties to generate tremendous impacts in the automotive, aerospace, and other industries that demand lightweight structural components in order to achieve high energy efficiency, which also means less air pollution. However, it is very difficult to achieve a good dispersion and capture of nanoparticles during solidification of metals. Effective nanoparticle incorporation into high temperature metal melts also presents a severe problem. Friction stir processing can serve as a powerful tool to disperse nanoparticles in the lightweight metal matrix nanocomposites fabricated by semi-solid processing at a relatively low temperature. This award supports fundamental research to provide knowledge needed to create a simple, novel and scalable manufacturing technology to drive metal matrix nanocomposites toward widespread applications. The research will attract, retain, and engage students from under-represented group. K-12 students/teachers and industry partners will be exposed to the new technology. Interdisciplinary curriculum materials will be developed to train graduate and undergraduate students.The objectives of this collaborative project are to (1) significantly advance the fundamental understanding of how friction stir processing interacts with nanoparticles in lightweight metal matrix nanocomposites, fabricated by semi-solid casting route, through a systematic experimental study on the nanoparticle movements and dispersion inside the grains during processing, and (2) understand the processing-microstructure-properties relations by investigating the effects of nanoparticle size and morphology, nanoparticle loading, and processing parameters on the micro/nano-structural evolution and the resultant mechanical properties of the nanocomposites. The metal matrix nanocomposites for the experimental study will be fabricated through a combination of semi-solid casting and friction stir processing to effectively incorporate nanoparticles in semi-solid state at a relatively-low temperature and disperse nanoparticles and refine microstructures in solid state to achieve superior properties. Through micro/nano materials analysis tools, this study will characterize micro/nano-structures, nanoparticle incorporation and distribution in alloys at semi-solid state and the nanoparticle dispersion by friction stir processing in metal matrix nanocomposites. Tensile and hardness (macro, micro, and nano) tests will be conducted to characterize the mechanical properties of the nanocomposites before and after friction stir processing.