NIRT/GOALI: Fundamental Study of Bulk Magnesium Matrix Nanocomposites Fabricated by Ultrasonic Cavitation Based Solidification Processing

摘要NIRT研究项目旨在推进基于超声空化的复杂块状镁基金属基纳米复合材料/部件的凝固工艺及其加工/结构/性能关系的基本认识和知识。计划了六个相互关联的研究任务。在任务1中，将开发一个基于超声空化铸造的功能实验系统，以证明大批量生产的可扩展性。任务2侧重于通过监测瞬态空化活动来理解这一过程，并优化这一过程，以实现纳米颗粒在Mg熔体中的均匀分散。任务3是表征所得纳米复合材料的微纳结构。研究纳米颗粒周围基体中的位错结构，以了解纳米颗粒强化的机理。任务4将执行铸造镁纳米复合材料的多尺度建模，以开发纳米结构如何影响性能的基本和定量理解。任务5将通过拉伸、蠕变、原位变形和疲劳研究、纳米压痕、断裂韧性和工具磨损测试，实验表征纳米颗粒对铸造Mg基纳米复合材料力学性能（在高温和室温下）的影响。任务6是通过将超声空化活动与实验和分析研究结果相关联，建立加工/结构/性能关系。铸造体镁合金基纳米复合材料可以显著提高汽车的能效和性能，对汽车和航空航天工业产生广泛的影响。教育部分包括威斯康星大学麦迪逊分校、加州大学戴维斯分校和佐治亚理工学院的多校区课程开发、研究学生交换和纳米技术意识计划（NAP），以吸引和吸引学生（来自大学和高中）和技术教育教师，特别是那些来自代表性不足群体的教师。外展活动将使更多的K-12学生、教师和行业接触到纳米技术。

Abstract 0506767The NIRT research program is to advance both the fundamental understanding and knowledge of ultrasonic cavitation based solidification processing of complex bulk magnesium-based metal-matrix nanocomposite materials/components and their processing/structure/property relationships. Six interrelated research tasks are planned. In Task 1, a functional experimental system for ultrasonic cavitation based casting will be developed to demonstrate scalability for high volume production. Task 2 focuses on the understanding of the process by monitoring transient cavitation activities and on the optimization of the process to achieve uniform nanoparticle dispersion in Mg melt. Task 3 is to characterize the micro/nano structure of the resultant nanocomposites. The dislocation structure in the matrix around nanoparticles will be examined to understand the mechanism of strengthening by nanoparticles. Task 4 will perform multi-scale modeling of cast Mg nanocomposites to develop a fundamental and quantitative understanding of how the nanoscale structure influences properties. Task 5 will experimentally characterize the effect of nanoparticles on the mechanical properties (at elevated temperatures as well as at room temperature) of cast Mg matrix nanocomposites by tensile, creep, in-situ deformation and fatigue studies, nano-indentation, fracture-toughness, and tool-wear testing. Task 6 is to establish the processing/structure/property relationships by correlating the ultrasonic cavitation activities with the results from the experimental and analytical studies.Cast bulk Mg alloy matrix nanocomposites can have a widespread impact on the automobile and aerospace industries by significantly improving the vehicle energy efficiency and performance. The educational components include multi-campus curriculum development at University of Wisconsin-Madison, University of California-Davis, and Georgia Institute of Technology, research student exchange, and a Nanotechnology Awareness Program (NAP) to attract and engage students (from colleges and high schools) and Technology Education teachers, especially those from underrepresented groups. Outreach activities will expose more K-12 students, teachers, and industries to nanotechnology.