Design of Bulk Stable Nanocrystalline Alloys: A New Approach to Lightweighting

块体稳定纳米晶合金的设计：轻量化的新方法

• 批准号: RGPIN-2022-02978
• 负责人: Tiamiyu, AhmedAlade
• 金额: $ 2.4万
• 依托单位: University of Calgary
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2022
• 资助国家: 加拿大
• 起止时间: 2022-01-01 至 2023-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=759774
• 关键词: Design; Bulk; Stable; Nanocrystalline; Alloys

Canada is committed to the United Nation's sustainable development goals to combat global climate change via the use of sustainable structures that minimize energy consumption and poisonous greenhouse gas (GHG) emissions. The approach adopted by major contributors-energy/transportation sectors-to tackling the climate change menace is lightweighting i.e., the replacement of heavy materials, say "stronger" steel, with lighter one like "softer" aluminum alloys; but this results in the loss of load-carrying capacity. Rather than trade-off strength upon lightweighting, the research here is proposing the use of the (i) same stronger "heavy" material but using less of it, and (ii) same softer "light" material but with improved strength, both offering even much better properties than what is commercially available. Because strength of materials increases with reduction in grainsize, the proposed lightweighting concept with improved strength is achieved by developing nanocrystalline (NC) materials-materials with ~1 to 100 nm in grain size (i.e., grain size is ~900 times smaller than the thickness of human hair). However, there is currently a global drawback in the use of NC materials-(a) nanograins grow even at room temperature, resulting in loss of strength and other functional properties, and (b) even if the nanograins are well stabilized against growth, they are limited to thin nanostructured coatings of ~1-100 microns thick. For lightweight applications to minimize energy consumption in the energy and transportation sectors, "bulk" NC materials with stabilized grain boundaries and with sizes/thicknesses beyond the current thin-film-scale are required. For clarity, "bulk" in this proposal refers to sample size/thickness from hundreds of centimeter- to meter- scale. A cost-effective and scalable approach to synthesize NC metals is through a powder processing route, but the success of producing bulk NC parts by powder processing rests on the consolidation process. This research program proposes a new approach that involves the union of two powder processes-solid-state mechanical milling to obtain nanograins, and cold spray additive manufacturing process for solid-state layer-by-layer deposition of the stabilized powders to developing bulk stable NC components; the nanograins will be stabilized by carefully selecting a solute that prefers the grain boundary sites of the solvent, thereby stabilizing it against grain growth. The success of this research will save Canada billions of dollars by reducing the cost of energy, emissions, and environmental impacts. The research program will also contribute to the (i) training of highly qualified personnel, (ii) UCalgary's mission to drive innovation, and (iii) Alberta's nanotechnology and manufacturing programs and research priorities-energy and GHG mitigation, and environment and climate adaptation target areas.

加拿大致力于实现联合国的可持续发展目标，通过使用可持续结构，最大限度地减少能源消耗和有毒温室气体排放，应对全球气候变化。主要贡献者-能源/运输部门-为应对气候变化威胁所采取的办法是轻量化的，即，用较轻的材料如“较软”的铝合金代替较重的材料，如“较强”的钢，但这会导致承载能力的损失。而不是权衡轻量化的强度，这里的研究建议使用（i）相同的更强的“重”材料，但使用更少，（ii）相同的更软的“轻”材料，但具有更高的强度，两者都提供比市售材料更好的性能。因为材料的强度随着晶粒尺寸的减小而增加，所以所提出的具有改进的强度的轻量化概念是通过开发纳米晶体（NC）材料来实现的，纳米晶体（NC）材料是晶粒尺寸为~1至100 nm的材料（即，颗粒尺寸比人类头发的厚度小~900倍）。然而，目前在NC材料的使用中存在一个全球性的缺点-（a）纳米颗粒甚至在室温下生长，导致强度和其它功能性质的损失，以及（B）即使纳米颗粒很好地稳定以防止生长，它们也限于约1-100微米厚的薄纳米结构涂层。对于轻量化应用，以最大限度地减少能源和运输部门的能源消耗，需要具有稳定晶界和尺寸/厚度超过当前薄膜规模的“散装”NC材料。为清楚起见，本提案中的“体积”是指数百厘米至米级的样品尺寸/厚度。合成NC金属的一种具有成本效益且可扩展的方法是通过粉末加工路线，但通过粉末加工生产批量NC零件的成功取决于固结过程。该研究计划提出了一种新的方法，涉及两种粉末工艺的结合-固态机械研磨以获得纳米颗粒，以及用于稳定粉末的固态逐层沉积的冷喷涂增材制造工艺，以开发块状稳定的NC部件;通过仔细选择优选溶剂的晶界位置的溶质来稳定纳米颗粒，从而使其稳定以防止晶粒生长。这项研究的成功将通过降低能源成本、排放和环境影响为加拿大节省数十亿美元。该研究计划也将有助于（一）高素质人才的培训，（二）卡尔加里大学的使命，以推动创新，和（三）阿尔伯塔的纳米技术和制造计划和研究重点能源和温室气体减排，环境和气候适应目标领域。