A Breakthrough Additive Manufacturing Method for High-Strength Lightweight 3D Micro-Architectured Materials

设计和制造具有上级机械性能如高强度的轻质材料是科学家和工程师面临的关键挑战之一。目前最先进的材料在重量和强度之间表现出剧烈的权衡，而多孔轻质材料的制造策略受到对材料结构的不良控制和有限的材料选择的影响。该项目研究了一种新的增材制造（AM）方法，该方法使用纳米颗粒的打印来制造一类新的三维（3D）微结构材料，该材料将具有低重量和高强度的理想特性。该研究还将纳入多尺度力学模型，考虑AM特有的微观结构和长度尺度的影响。研究结果将通过快速制造具有定制架构和材料的3D结构来推进AM领域，这些结构和材料具有广泛的应用，包括生物医学植入物，多孔膜，组织工程和能量存储。将招募少数民族和女性本科生和研究生研究人员参与该项目，并将定期开展有针对性的活动，以吸引K-12学生进入制造业研究专业。 该研究的重点是研究一种新型的增材制造方法，该方法涉及将金属纳米颗粒分散到溶剂中，然后进行纳米颗粒烧结，以实现高度复杂和可控的3D金属结构，这些结构重量轻，强度高。该项目的第一个目标是研究印刷过程的科学原理。模型将被开发，以确定液滴冷凝，溶剂蒸发和系统动力学的3D架构的形成中的作用。这些模型将指导实验，这些实验涉及将银、镍或铝纳米颗粒分散到乙二醇等溶剂中，并使用气溶胶喷射3D打印机打印3D结构。这项工作的第二个目标是确定的微观和纳米级的变形机制，控制的金属三维结构的机械行为。复杂的3D晶格（孔隙率高达94%）和微柱将通过打印制造，并在压缩和弯曲下进行测试。将开发多尺度力学模型，考虑位错运动，应力和应变梯度，以及微观结构的变化。这些模型将预测最佳的3D设计，大大提高强度重量比，这将通过机械测试进行验证。该项目的结果将是一种新型的增材制造平台，可以创建强大的轻质结构，其长度范围超过五个数量级（几十纳米到几毫米）的建筑控制，并可能开辟新的研究领域3D架构的制造和增材制造零件机械行为的建模方法。

The design and manufacture of lightweight materials having superior mechanical properties such as high strength is one of the key challenges for scientists and engineers. Current state-of-the-art materials show a drastic tradeoff between weight and strength, while manufacturing strategies for porous lightweight materials suffer from poor control over material architecture and limited material choices. This project investigates a novel additive manufacturing (AM) method that uses printing of nanoparticles to fabricate a new class of three-dimensional (3D) micro-architectured materials, which will possess the desired characteristics of low weight and high strength. The research will also incorporate multi-scale mechanical models that consider the effect of microstructures and length scales specific to AM. The research results will advance the field of AM by enabling rapid fabrication of 3D structures with custom architectures and materials that have a wide range of applications, including biomedical implants, porous membranes, tissue engineering, and energy storage. Minority and women undergraduate and graduate researchers will be recruited to work on the project and periodic activities will be carried out targeted to attract K-12 students into the manufacturing research profession. The research focuses on the investigation of a novel additive manufacturing method that involves printing of metal nanoparticles dispersed into a solvent, followed by nanoparticle sintering to realize highly intricate and controlled 3D metal architectures that are lightweight and strong. The first objective of the project is to investigate the scientific principles governing the printing process. Models will be developed that identify the role of droplet condensation, solvent evaporation, and system dynamics in the formation of the 3D architectures. The models will guide experiments that will involve printing of 3D architectures from silver, nickel, or aluminum nanoparticles dispersed into a solvent such as ethylene glycol, and using an Aerosol Jet 3D printer. The second objective of this work is to identify the micro and nanoscale deformation mechanisms governing the mechanical behavior of the metallic 3D structures. Complex 3D lattices (with up to 94% porosity) and micro-pillars will be fabricated by printing, and tested under compression and bending. Multi-scale mechanical models will be developed that consider dislocation motion, stress and strain gradients, and variability in the microstructure. The models will predict optimal 3D designs that improve strength-to-weight ratio dramatically, which will be verified through mechanical tests. The result of this project will be a novel additive manufacturing platform that can create strong lightweight structures with architectural control of over five orders of magnitudes in length scale (tens of nanometers to several millimeters), and will potentially open up new research areas in the manufacturing of 3D architectures and modeling methods for mechanical behavior of additively manufactured parts.