Deformation Physics of Nanoscale Features in Magnesium Alloys

镁合金纳米级特征的变形物理学

• 批准号: RGPIN-2019-05882
• 负责人: ZHU, GUOZHEN
• 金额: $ 2.77万
• 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: 2020
• 资助国家: 加拿大
• 起止时间: 2020-01-01 至 2021-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=714657
• 关键词: Deformation; Physics; Nanoscale; Features; Magnesium

Magnesium alloys can achieve a high strength-density ratio and thus attract continuous interest over decades in replacing conventional metals for the weight reduction in vehicles and aircrafts. The main impediment to the greater use of magnesium is their poor deformability, originating from the inherent anisotropy of the crystal structure of magnesium. In detail, the activation thresholds for various deformation modes, such as basal-slip, non-basal slip, and twinning, are largely different (i.e., of order 100). With current emphasis on improving the deformability of magnesium alloys while increasing their strength, the key is tuning the relative activities of different deformation modes, mainly through introducing nanoscale features with selective strengthening effects. Alloying with rare earth elements, magnesium shows promise in improving both strength and ductility, however, the involved mechanism is poorly understood due to its complexity, including unclear nanoscale features, their interaction with different deformation modes, and consequent strengthening effects. The five-year objective of the proposed research is to perform a systematic and comprehensive research to gain an adequate understanding of the deformation physics within magnesium alloys at atomic and nano scale. Using state-of-the-art in-situ thermo-mechanical testing and high resolution imaging techniques integrated with electron microscopy, research will be undertaken, with model systems of binary and ternary magnesium-rare earth alloys, in three areas: 1) the effect of rare earth solutes on the structure changes of different dislocations, the main carriers of plastic deformation; 2) the interaction between dislocations and twin boundaries and grain boundaries, containing rare earth segregations; and 3) the selective strengthening effects of solute clusters or fine precipitates with anisotropic morphology. The expected major outputs of this research will be an enhanced understanding of nanoscale features and consequent strengthening effects within magnesium alloys. These results will provide a comprehensive understanding of deformation dynamics at atomic and nano scale in magnesium alloys, and can form a solid foundation for further advancing hexagonal alloys in general. The proposed program will train 3 Ph.D. and 3 master's students, who will gain experience and will generate new knowledge in microstructure design and characterization of light-weight alloys. This work will be of great value to the key industries involved in light-weight alloys, such as General Motors and Magellan Aerospace. Discoveries in the areas of magnesium will help maintain Canada's status as a leader in this research area and in the production of light-weight alloys in aerospace and automotive industries.

镁合金可以达到高强度比率，从而在数十年中吸引了连续的兴趣，以替换传统的金属减轻车辆和飞机的重量。更多地使用镁的主要障碍是它们的变形性差，源自镁晶体结构的固有各向异性。详细说明，各种变形模式的激活阈值，例如基底滑动，非基质滑移和孪生，在很大程度上不同（即100阶）。由于目前强调提高镁合金的变形性，同时提高其强度，关键是调整不同变形模式的相对活性，主要是通过引入纳米级特征具有选择性加强效应。镁与稀土元素的合金合金显示出有望改善强度和延展性的有望，但是，由于其复杂性，包括不明确的纳米级特征，与不同变形模式的相互作用以及随之而来的增强作用，所涉及的机制得以了解。 拟议的研究的五年目标是进行系统，全面的研究，以足够了解原子和纳米量表的镁合金中的变形物理学。将使用与电子显微镜集成的最新原位热力学测试和高分辨率成像技术，并在三个区域内使用二进制和三元镁 - 稀土的二进制和三元镁 - 稀土地球合金的模型系统进行研究：1）稀土溶质对不同脱位的结构变化的影响，主要塑料塑料型的主载体； 2）位错和双边界和晶界之间的相互作用，包含稀土种族隔离； 3）具有各向异性形态的溶质簇或细沉淀的选择性加强作用。 这项研究的预期主要输出将是对纳米级特征的增强理解，并在镁合金中增强效果。这些结果将为镁合金的原子和纳米尺度上的变形动力学提供全面的理解，并可以为总体上进一步前进的六角合金构成坚实的基础。拟议的计划将培训3博士学位。还有3位大师的学生，他们将获得经验并将在微型赋予合金的微观结构设计和表征方面产生新知识。这项工作对参与轻型合金的主要行业（例如通用汽车和麦哲伦航空航天）具有很高的价值。镁领域的发现将有助于维持加拿大在这一研究领域的领导地位，以及在航空航天和汽车行业中产生的轻质合金的生产。