Size-Dependent Strength and Plasticity in Metallic Nanocrystalline-Amorphous Composites

金属纳米晶非晶复合材料中尺寸相关的强度和塑性

• 批准号: 430800-2013
• 负责人: Deng, Chuang
• 金额: $ 1.82万
• 依托单位: University of Manitoba
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=648999
• 关键词: Size; Dependent; Strength; Plasticity; Metallic

Materials that are strong and ductile are always favored and highly demanded by industry. However strength and ductility are usually anti-correlated in materials and are difficult to achieve simultaneously. While monolithic nanocrystalline metals and amorphous metallic glasses both exhibit higher strength as compared to conventional metals and alloys, their brittle natures severely limit their application as engineering materials. ****Some prior studies suggest that introducing a small portion of amorphous phase in nanocrystalline materials or vice versa can significantly improve the ductility of these materials without sacrificing the strength. For instance, exceptional tensile ductility up to ~13.8% elongation has been reported in crystalline Cu/CuZr glass nanolaminates as compared to < 2% in conventional nanocrystalline Cu. It has also been observed that introduction of ~7% volume fraction of nanocrystals can increase the compressive ductility of amorphous CuZr bulk metallic glass to > 5% from nearly zero. Although such investigations were based on trial-and-error and a deep understanding of the deformation mechanisms is still lacking, it opens the door to design materials and novel structures with desired strength and ductility at the same time. ****The applicant proposes to use mainly atomistic simulation and subsequent in-situ deformation experiments to study the strength and plasticity and their dependence on microstructures of crystalline/amorphous composites. The proposed study will significantly advance current understanding of the microplasticity in amorphous metallic glass and crystalline/amorphous composites in confined volumes. Ultimately, the research will contribute to the design of novel structures and materials with optimized combination of strength and ductility that can be used for various industrial applications, for example in microelectromechanical systems and nanoelectro-mechanical systems.**

强大和延性的材料总是受到行业的青睐和高度要求。但是，强度和延展性通常在材料中抗相关，并且很难同时实现。与常规金属和合金相比，虽然单片纳米晶金属和无定形金属眼镜的强度都更高，但它们的脆性明显限制了它们作为工程材料的应用。 ****一些先前的研究表明，在纳米晶体材料中引入一小部分非晶相，反之亦然，可以显着改善这些材料的延展性而无需牺牲强度。例如，在晶体Cu/Cuzr玻璃纳米胺中报道了高达〜13.8％的伸长延展，而常规纳米晶体CU的伸展性延长率为<2％。还可以观察到，纳米晶体的引入〜7％的体积分数可以增加无定形cuZR块状金属玻璃的压缩性，从近乎零> 5％。尽管此类研究是基于反复试验的，并且仍然缺乏对变形机制的深刻理解，但它为设计材料和新型结构打开了大门，同时具有所需的强度和延展性。 ****申请人建议主要使用原子模拟和随后的原位变形实验，以研究强度和可塑性及其对晶体/无定形复合材料微结构的依赖。拟议的研究将显着提高当前对无定形金属玻璃和晶体/无定形复合材料的微塑性的理解。最终，这项研究将有助于设计具有优化强度和延展性组合的新型结构和材料，可用于各种工业应用，例如在微机械系统和纳米机械系统中。**