CAREER: Towards High Strength Corrosion-Resistant Magnesium Alloys

为了满足当前的技术、社会经济和环境挑战，对轻质、高强度和耐腐蚀合金的需求不断增加。镁是第三丰富的金属，是所有结构金属中最轻的，因此在航空航天、汽车和基础设施应用等许多行业中引起了极大的关注。镁合金还具有良好的生物相容性和支持骨生长，因此这些合金也被认为是生物医学应用的候选材料。然而，镁合金在这些应用中的使用是有限的，但是它们对环境降解的耐受性差并且强度低。减轻镁合金腐蚀同时提高强度的能力可能会彻底改变汽车和航空航天工业以及生物材料领域。该学院早期职业发展计划（CAREER）奖支持研究，以了解镁合金的强度和耐腐蚀性的基本机制，其目标是提供对性能的前所未有的控制，并使其能够为特定的技术应用定制这些材料。这项工作还纳入了深远的教育和推广目标，以激励学生在等级K-12追求STEM学科的教育;招募，留住和支持优秀和多样化的学生团体在本科和研究生水平;并为学生提供主动学习的机会，导师，和奖学金相关的研究领域。该研究项目包括为高中生提供研究机会，与高中教师合作，激发年轻学生对STEM领域的兴趣，扩大代表性不足的群体的参与。该研究将有助于对亚稳纳米晶镁合金的性质以及实现高强度和耐腐蚀镁合金的机制的基本理解。受不锈钢中“不锈”现象的启发，将采取一种创新的方法来提高镁合金的机械强度和耐腐蚀性。本研究的具体目标是：1）制备具有宽晶粒度、金属间化合物弥散性和合金元素固溶度的镁合金，2）研究纳米晶结构、金属合金元素固溶度和金属间化合物对腐蚀和力学性能的影响; 3）确定镁合金腐蚀和机械性能同时改善的关键机制，该奖项反映了NSF的法定使命，通过使用基金会的知识价值和更广泛的影响审查标准进行评估，认为值得支持。

In order to meet current technological, socio-economic and environmental challenges, the need for lightweight, high strength and corrosion resistant alloys is increasing continuously. Magnesium, the third most abundant metal, is the lightest of all structural metals and therefore has attracted significant attention for a number of industries including aerospace, automotive, and infrastructure applications. Magnesium alloys also possess excellent biocompatibility and support bone growth, and thus these alloys are also considered candidate materials for biomedical applications. The use of magnesium alloys in these applications, however, is limited but their poor resistance to environmental degradation and low strength. The ability to mitigate the corrosion of magnesium alloys while simultaneously increasing the strength could revolutionize the automotive and aerospace industries, as well as the field of biomaterials. This Faculty Early Career Development Program (CAREER) award supports research to understand the fundamental mechanisms of both strength and corrosion resistance in magnesium alloys, with the goal of providing unprecedented control over the properties and making it possible to tailor these materials for specific technical applications. The work also incorporates far-reaching educational and outreach objectives to inspire students in grades K-12 to purse education in STEM disciplines; to recruit, retain and support outstanding and diverse student groups at undergraduate and graduate levels; and to provide students the opportunities for active learning, mentorship, and scholarship related to this research areas. The outreach programs include research opportunities to high school students, working with the high school teachers to stimulate interests in STEM fields among young students and broaden participation of underrepresented groups.This research will contribute to the fundamental understanding of the properties of metastable nanocrystalline magnesium (Mg) alloys and the mechanisms that can enable high strength and corrosion resistant Mg alloys. Inspired by the phenomenon causing the "stainless" behavior in stainless steels, an innovative approach of improving mechanical strength and corrosion resistance of Mg alloys will be undertaken. The specific objectives of this research are to: 1) produce Mg alloys with a wide range of grain size, dispersion of intermetallics, and solid solubility of the alloying element; 2) study the influence of the nanocrystalline structure, the solid solubility of the metal alloying elements, and intermetallics on corrosion and mechanical properties; 3) identify the key mechanisms causing simultaneous improvement in corrosion and mechanical properties of magnesium alloys, and develop a theoretical framework for designing high strength corrosion resistant magnesium alloys.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.