Fundamental Simulation Studies of Mixing at Sliding Interfaces

滑动界面混合的基本模拟研究PI - Falk，密歇根大学这项资助的研究人员和学生使用原子尺度上的计算机模拟来模拟两种材料相互滑动时表面发生的混合。在滑动过程中，材料对升高的应力的反应方式与混合进行的方式密切相关。这些过程对工程的几个领域都很重要，包括摩擦力的预测，这会导致能源的低效利用，以及磨损，这会导致机器和设备的退化和故障。更好地了解滑动界面的混合对于开发新的固态连接工艺（如摩擦焊接和搅拌摩擦焊接）也至关重要，这些工艺可能会消除目前用于连接金属的对环境有害和/或有毒工艺的需要。这些连接工艺为铝合金的连接提供了安全、经济、可靠的方法。这些轻质合金在汽车应用中的增加使用对于提高车辆的燃油经济性标准以减少其对环境的影响至关重要。用这种方法混合固态金属也可以制造出新的合金。模拟了多种不同的金属材料，包括金属玻璃和纳米晶体金属，并将模拟结果与实验文献进行了比较。该研究为理解表面处理、微观组织和力学性能之间的联系提供了新的途径。本研究的目的是为建立金属合金微观组织发展和力学混合的预测模型奠定基础。此外，研究者正在开发研究生教育方法，提供将模拟与实验联系起来的专业知识。作为这项研究的一部分而开发的计算方法正在被纳入研究者教授给大约200名一年级学生的计算机编程入门课程中，并被纳入到推广工作中。这些努力旨在通过展示模拟对社会的潜在影响，鼓励学生从事计算科学和计算机相关学科的职业。

NSF 0510163Fundamental Simulation Studies of Mixing at Sliding Interfaces PI - Falk, University of MichiganThe investigator and student supported by this grant employ computer simulation on the atomic scale to model the mixing that occurs at the surface when two materials slide against one another. During sliding the way the material responds to elevated stress is intimately connected to the way in which mixing proceeds. These processes are important to several areas of engineering including the prediction of friction, which results in the inefficient use of energy, and wear, which results in the degradation and failure of machines and devices. A greater understanding of mixing at sliding interfaces is also critical for the development of new solid-state joining processes such as friction welding and friction-stir welding that can potentially obviate the need for environmentally harmful and/or toxic processes currently used to join metals. These joining processes have proved important in providing safe, cost-effective and reliable methods for joining of aluminum alloys. The increased use of these lightweight alloys in automotive applications will be critical for increasing fuel economy standards of vehicles to decrease their environmental impact. New alloys can also be created by using such processes to mix metals in the solid state. A variety of different metallic materials are being simulated including metallic glasses and nano-crystalline metals, and the simulations are being compared with the experimental literature. This research provides new ways of understanding the connection between surface treatment, microstructure and mechanical properties. The aim of this research is to establish the foundation for predictive models of microstructure development and mechanical mixing in metal alloys. In addition the investigator is developing graduate education methodologies that provide expertise in relating simulation to experiment. Computational methods developed as part of this research are being incorporated in the introductory computer programming class the investigator teaches to approximately 200 first-year students and in to outreach efforts. These efforts aim to encourage students to pursue careers in computational science and computer-related disciplines by showing the potential impact of simulation on society.