Manufacturing USA/GOALI: Visualizing Nanoscale Evolution during Aluminum Alloy Melt Processing

减轻陆上、海上和空中运送人员和货物的车辆重量对于提高燃油经济性和增加特派团有效载荷至关重要。铝合金因其高强度/重量比而被用于汽车和航空航天工业中以满足这一需求。然而，为了提高燃料效率，需要更高的强度和更轻的合金，这可以通过在铝基中加入纳米颗粒来实现。基于将气泡直接引入铝熔体中，开发了一种新的制备纳米颗粒的方法。向熔体中吹入氮气可以产生50纳米大小的氮化铝颗粒。这一学术联系机会奖(GOALI)支持基础研究，以提供控制颗粒大小和形状所需的知识，从而优化机械性能和性能。这项研究的结果将使工业能够将这一过程从实验室的小熔体扩大到商业尺寸的钢锭，这将使地面、空中和海上运输用的轻质合金的开发成为可能，从而直接为美国经济带来好处。参与这项研究的学生将有机会与团队中来自行业的工程师互动。将采用实验和建模相结合的方法，为材料工程教育奠定新的基础。外联活动强调对妇女和任职人数偏低的少数群体的指导。研究表明，添加50-200纳米粒子可以提高铝合金的强度和高温稳定性。然而，由于纳米颗粒的团聚和纳米颗粒-基质界面结合不充分，导致复合材料的力学性能经常下降。一种新的方法，即通过原位气液反应直接在金属熔体中生成增强纳米颗粒，可以生成纳米级分散的AlN和TiC颗粒。在这个项目中，将研究支配这一过程的纳米到微结构的动力学。这些基础研究将指导确定大规模原位铝纳米复合材料制造的工艺条件窗口，从而产生具有最佳机械性能的纳米颗粒形态和分布。为了研究纳米尺度的热力学和动力学过程，将利用原位反射高能电子衍射(RHEED)在分子束外延(MBE)系统中对合金进行氮化。对于原位3D纳米颗粒可视化，将开发一种微型熔融器，并将使用基于同步加速器的X射线纳米层析成像技术实现纳米复合材料的3D可视化。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

Reducing the weight of vehicles that move people and goods on land, sea and air is critical for improving fuel economy and increasing mission payload. Aluminum alloys are used in the automotive and aerospace industries to meet this need because of their high strength-to-weight ratio. For improved fuel efficiency, however, higher strength and lighter weight alloys are needed, and this can be achieved though the incorporation of nanosized particles in the aluminum matrix. A novel approach to producing the nanoparticles has been developed based on the introduction of gas bubbles directly into the molten aluminum. Blowing nitrogen gas into the melt can produce aluminum nitride particles that are 50 nanometers in size. This Grant Opportunities for Academic Liaison with Industry (GOALI) award supports fundamental research to provide the knowledge needed to control the particle size and shape which lead to optimized mechanical properties and performance. The results from this research will enable industry to scale up this process from small laboratory melts to commercial size ingots, which will enable the development of lightweight alloys for ground, air, and sea transportation, with direct benefit to the U.S. economy. The students involved in this research will have the opportunity to interact with the engineers from industry who are part of the team. An integrated experimental and modeling approach will be utilized, which is forming the new basis for materials engineering education. Outreach activities emphasize the mentoring of women and underrepresented minorities. The incorporation of 50-200 nanometer particles has been shown to improve the strength and high temperature stability of aluminum alloys. However, due to agglomeration of the nanoparticles and insufficient bonding at the nanoparticle-matrix interface, the mechanical properties of the composite material are often degraded. A new approach, in which the reinforcing nanoparticles are generated directly in the molten metal via an in-situ gas-liquid reaction has been shown to produce nanosized, dispersed AlN and TiC particles. In this project, the nano- to micro- structural dynamics governing the process will be investigated. Insights from these fundamental studies will guide the identification of a process condition window for large-scale in-situ aluminum nanocomposite manufacturing, which produces a nanoparticle morphology and distribution with optimum mechanical properties. To examine the nanometer-scale thermodynamic and kinetic processes, in-situ reflection high-energy electron diffraction (RHEED) will be utilized during alloy nitridation in a molecular-beam epitaxy (MBE) system. For in-situ 3D nanoparticle visualization, a mini-melter will be developed and 3D visualization of the nanocomposites will be achieved using synchrotron-based X-ray nanotomography.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.