CAREER: Microstructure and Size Effects on Metal Plasticity at Limited Length Scale

技术支持：只有充分理解微观结构和样品尺寸的影响，才能在一维金属纳米线中获得与强度和塑性相关的有意义的结果。这些研究活动的两个焦点是（1）使用并行原子模拟来表征金和镍纳米线中晶格位错和特殊晶界之间的复杂相互作用，以及（2）使用应用电化学方法和原子力显微镜测量具有受控微观结构和晶粒尺寸的金和镍纳米线的强度、延展性和应变率敏感性。这将使PI能够从理论上和实验上证明特殊的晶界，如孪晶界，可以显着改善纳米线的这些特性。智力上的优点在于一个综合的实验/建模研究方法的介绍，利用原子模拟和原子力显微镜的力量。这种方法的组合将是非常成功的弥合实验和建模之间的差距差距在个别纳米积木材料的机械特性。这种方法的另一个潜在结果是可以快速帮助建立新的标准方法和校准程序来测试纳米线，如薄膜的纳米压痕技术，开辟新的研究领域并导致更多的发现。这项研究还有望展示制造具有特定缺陷的纳米棒和纳米线的新方法，这些缺陷使纳米棒和纳米线更坚固。非技术：这个5年计划的教育部分是强有力的整合到多学科研究计划。PI将在佛蒙特大学（UVM）做出重大的教育和推广贡献，以（1）率先修订研究生工程计划，重点是多尺度系统和建模;（2）通过现有的国际学生交流计划（ISEP），在本科阶段与八个欧洲工程专业的国际学生交流;以及（3）通过一种与摄影艺术交叉的新颖的科学成像，制定一项有力的推广计划，以改善佛蒙特州北方农村高中和密斯克山谷社区阿贝纳基印第安部落的工程学学生的招聘情况。这个职业奖也将广泛推进该领域的理解，同时促进参与研究项目的本科生和研究生的教育培训。特别是，该奖项预计将加强学生在高性能和并行计算以及高分辨率成像领域的教育。研究生还将有机会在国家会议和会议上广泛传播研究成果，以提高对该领域的科学认识。该CAREER奖将鼓励使用多用户设施，UVM新成立的佛蒙特州高级计算中心，并涉及美国能源部新的国家研究设施的科学家的参与。这个职业奖的教育计划将广泛振兴材料科学和工程在UVM的兴趣，帮助招募工程学生从代表性不足的群体，并提高学生的多元文化培训。

TECHNICAL: Meaningful results related to strength and plasticity in one-dimensional metallic nanowires can only be achieved if the influences of microstructure and sample size are fully understood. The two foci of these research activities are to (1) use parallel atomistic simulation to characterize the complex interactions between lattice dislocations and special grain boundaries in gold and nickel nanowires, and (2) measure the strength, ductility and strain-rate sensitivity of gold and nickel nanowires with controlled microstructures and grain size using applied electrochemical methods and atomic force microscopy. This would enable the PI to prove both theoretically and experimentally that special grain boundaries such as twin boundaries can dramatically improve these properties in nanowires. The intellectual merit lies in the presentation of a combined experimental/modeling research approach harnessing the power of both atomistic simulation and atomic force microscopy. This combination of methodologies will be very successful in bridging the gap between experiment and modeling in the mechanical characterization of individual nano-building block materials. Another potential outcome of such approach can be to rapidly help establish new standard methods and calibration procedures to test nanowires, as well-defined as nanoindentation technique for thin films, open up new research areas and lead to more findings. The research is also expected to show new ways to fabricate nanorods and nanowires with specific defects that make them stronger. NON-TECHNICAL: The educational component of this 5-year plan is strongly integrated to the multidisciplinary research program. The PI will make major educational and outreach contributions at the University of Vermont (UVM) to (1) spearhead the effort of revising the graduate engineering program with a focus on Multiscale Systems and Modeling; (2) structure international student exchanges with eight European engineering-specific programs at undergraduate level via the existing International Student Exchange Program (ISEP); and (3) develop a vigorous outreach program, via a novel scientific imaging which cross-cuts with the photographic arts, to improve the recruitment in engineering of students from rural high schools in Northern Vermont and the Abenaki Indian tribe in the Missisquoi Valley community. This CAREER award will also broadly advance the understanding in the field while promoting educational training of undergraduate and graduate students involved in the research project. In particular, this award is expected to enhance the education of students in the area of high performance and parallel computing, and high-resolution imaging. The graduate students will also have opportunities to broadly disseminate the results of the research at national conferences and meetings to enhance scientific understanding in the field. This CAREER award will stimulate the use of a multi-user facility, UVM's newly-established Vermont Advanced Computing Center, and involve the participation of scientists at a new US DOE's national research facility. The education program of this CAREER award will broadly revitalize the interest for materials science and engineering at UVM, help recruit engineering students from underrepresented groups, and improve the student's multicultural training.