GOALI: Computational Materials Science Approach to Study Precipitation-Hardening Magnesium-Zinc-Rare Earth (Mg-Zn-RE) Alloys

GOALI：研究沉淀硬化镁锌稀土 (Mg-Zn-RE) 合金的计算材料科学方法

• 批准号: 1005762
• 负责人: Donald Stone
• 金额: $ 56万
• 依托单位: University of Wisconsin-Madison
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-09-15 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1005762&HistoricalAwards=false
• 关键词: GOALI; Computational; Materials; Science; Approach

TECHNICAL SUMMARY: It is proposed to study phase equilibria and mechanical properties in Mg-Zn-RE (rare earth: Nd, Ce, Sm) alloys. Zn additions were found to provide an avenue for heat treatment analogous to GP zone formation in Al-Cu alloys. Results have shown that RE additions dramatically improve mechanical properties, but most research so far has been by trial and error. The proposed study adopts a computational materials design approach to optimize Mg-Zn-Nd(Ce, Sm) alloys for the best combination of mechanical properties in the as-fabricated (cast and extruded) and heat-treated conditions. The proposed study (1) produces thermodynamic descriptions of the Mg-Zn-Nd(Ce, Sm) systems; (2) carries out directional solidification of representative alloys to characterize structures and compositions of the phases formed and solidified microstructures, in the context of the phase diagrams obtained; (3) measures the mechanical properties of selected alloys in the solidified state and after specific thermal treatment. Bulk mechanical properties (yield strength, ultimate tensile strength, hardness, ductility) are characterized. Nanoindentation will be used to relate bulk properties to processes going on at the micro-scale and to examine the mechanical properties of the individual phases. The intellectual merit of this research includes the use of computational thermodynamics coupled with key experiments to rapidly obtain thermodynamic descriptions of Mg-Zn-RE. This approach differs from traditional ones that rely only on experiments, which are tedious and ineffective for multi-component systems. The thermodynamic descriptions obtained can be used to provide appropriate thermodynamic quantities as input for kinetic models, for predicting microstructures and, ultimately, mechanical properties.NON-TECHNICAL SUMMARY: Magnesium is the lightest structural metal, and researchers worldwide are motivated by the promise of improved fuel economy and reduced environmental impact to develop magnesium alloys for replacing steel and aluminum in automotive applications. To address this goal the present research uses a computational thermodynamics approach to develop a new class of promising magnesium-zinc-rare earth (Nd, Ce, Sm) alloys in a manner that is more efficient and accurate than has been achieved previously. The mechanical properties (strength) of the alloys will be tested against the micro- and nanoscale properties of the phases inside the alloys, so that the knowledge gained will lead to better understanding for future development of other kinds of alloys. This work involves collaboration among researchers from the University of Wisconsin and General Motors. The broader impact of the proposed work includes an opportunity for young people - future scientists and engineers - to experience working on a broad, fundamental problem with both academic and industrial importance and under the supervision of both industrial and academic advisors. The students will gain the invaluable experience of working on a portion of their research in an industrial environment, i.e. at the General Motors R&D Center.

技术摘要：提议研究MG-Zn-RE（稀土：ND，CE，SM）合金的相位平衡和机械性能。发现Zn添加为与Al-Cu合金中GP区形成类似的热处理提供了一条途径。结果表明，RE添加大大提高了机械性能，但是到目前为止，大多数研究都是通过反复试验。拟议的研究采用了一种计算材料设计方法来优化MG-ZN-ND（CE，SM）合金，以在拟合（铸造和挤出）和热处理条件下提供机械性能的最佳组合。拟议的研究（1）产生了MG-ZN-ND（CE，SM）系统的热力学描述； （2）在获得的相图的背景下，对代表合金的定向凝固来表征形成和固化微观结构的相结构和组成； （3）测量在固化状态下和特定热处理后选定合金的机械性能。表征了大量的机械性能（屈服强度，最终拉伸强度，硬度，延展性）。纳米指标将用于将批量特性与在微尺度上进行的过程相关联并检查单个相的机械性能。这项研究的智力优点包括使用计算热力学以及关键实验来快速获得MG-ZN-RE的热力学描述。这种方法与仅依靠实验的传统方法不同，这些方法对多组分系统乏味且无效。获得的热力学描述可用于提供适当的热力学数量，作为动力学模型的输入，预测微观结构，最终是机械性能。没有技术摘要：镁是结构金属的最轻的结构金属，全世界的研究人员都会受到燃油经济性和降低环境影响的良好型镁和量身材的积极性，以替代镁质和远离镁质的镁质量。为了解决这一目标，本研究采用计算热力学方法来开发一种新的有前途的镁稀土（ND，CE，SM）合金，其方式比以前更有效，更准确。合金的机械性能（强度）将针对合金内相的微观和纳米级特性进行测试，因此获得的知识将有助于更好地理解其他合金的未来开发。这项工作涉及威斯康星大学和通用汽车的研究人员之间的合作。拟议工作的更广泛的影响包括为年轻人（未来的科学家和工程师）的机会，可以经历在学术和工业重要性以及工业顾问和学术顾问的监督下处理广泛，根本的问题。学生将获得在工业环境中进行部分研究的宝贵经验，即在通用汽车研发中心。