Computational Study of the Generation of Crystal Defects and Controlled Modification of Surface Microstructure by Short Pulse Laser Irradiation

短脉冲激光辐照晶体缺陷产生及表面微结构可控改性的计算研究

• 批准号: 0907247
• 负责人: Leonid Zhigilei
• 金额: $ 27.17万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0907247&HistoricalAwards=false
• 关键词: Computational; Study; Generation; Crystal; Defects

This award supports computational and theoretical research, and education aimed at investigation of a range of fast non-equilibrium processes responsible for material modification and surface nanostructuring by pico- and femtosecond scale laser pulses. The research involves large-scale simulation and has potential for making a transformative impact on the fundamental understanding of material response and microstructure evolution under extreme conditions of ultrafast heating and cooling, as well as for opening new directions for controlled laser material modification with nanoscale resolution. The goal of this research program is to reveal, through large-scale atomistic simulations, the fundamental processes responsible for the modification of surface microstructure of metal targets irradiated by short laser pulses. A computational model combining the molecular dynamics method with a continuum description of the electron heat conduction and electron-phonon coupling will be used to perform a detailed analysis of the mechanisms of laser-induced generation of crystal defects and their role in the evolution of surface microstructure and atomic mixing. The conditions leading to the formation of a nanocrystalline surface structure and the atomic-level processes controlling the nucleation and growth of crystallites within a strongly undercooled liquid region of the target will be investigated with a particular focus on the effect of the free surface on the nucleation kinetics and crystallographic orientation of the new grains. The relative contribution of different diffusive and non-diffusive mechanisms of atomic mixing occurring under conditions of rapid melting/solidification, plastic deformation and laser-induced supersaturation with point defects will be investigated in combined molecular dynamics and kinetic Monte Carlo simulations performed for binary alloys and multi-layered targets. The physical processes responsible for the formation/stabilization of metastable crystalline and amorphous phases will be investigated and related to the irradiation conditions in short pulse laser processing. This award supports educational initiatives in the areas of scientific computing and laser-materials interactions include the active involvement of graduate and undergraduate students into various aspects of high-performance computing, development of a new graduate course on Laser-Materials Interactions, as well as incorporation of the research results into an existing course, Introduction to Atomistic Simulations. The PI will continue to maintain close contacts with the Office of Minority Programs in recruiting undergraduate students from traditionally under-represented groups. International collaborations with groups from Germany, France, Russia, and Iraq will involve short and long-term mutual visits and will enrich the educational and cultural experience of the participating graduate and undergraduate students. The educational component of this project also includes a design of an interactive web-site ?Materials under Extreme Conditions.? A non-technical description of general concepts of ultrafast materials phenomena induced by short pulse laser irradiation will be illustrated by the research results obtained in this program and presented in the form of images, computer animations, and simple interactive simulations.

该奖项支持计算和理论研究，旨在调查一系列快速非平衡过程，负责通过PICO-和飞秒量表激光脉冲进行材料修饰和表面纳米结构。该研究涉及大规模的模拟，并具有对超快加热和冷却的极端条件下对材料响应和微观结构演化的基本理解的转化影响，以及打开新的方向，以通过纳米级分辨率进行控制激光材料修饰。该研究计划的目的是通过大规模的原子模拟揭示了负责修饰短激光脉冲辐照的金属靶标表面微观结构的基本过程。将分子动力学方法与电子热传导和电子偶联的连续描述相结合的计算模型将用于对激光诱导的晶体缺陷的机制进行详细分析及其在表面微观结构和原子混合的演变中的作用。将研究导致纳米晶体表面结构形成的条件以及控制靶标在强底冷液体区域内的晶体成核和生长的原子级别的过程，并将特别关注新晶粒的核表面对成核动力学动力学和晶体学方面的特定效果。在快速融化/固化，塑性变形和激光诱导的过饱和的情况下，与点缺陷的相对贡献，在二元组合和动力学蒙特卡洛模拟中针对二进制Alloys和多层型靶标进行了相对的原子混合机制的相对贡献。将研究负责亚稳态晶体和无定形相的形成/稳定的物理过程，并与短脉冲激光器加工中的辐射条件有关。该奖项支持科学计算和激光材料相互作用领域的教育计划，包括将研究生和本科生的积极参与参与高性能计算的各个方面，开发有关激光 - 材料互动的新研究生课程，以及将研究结果纳入现有课程，引入了对现有的模拟。 PI将继续与少数民族计划办公室保持密切联系，以招募传统代表性不足的团体的本科生。与来自德国，法国，俄罗斯和伊拉克的团体的国际合作将涉及短期和长期的相互访问，并将丰富参与毕业生和本科生的教育和文化经验。该项目的教育部分还包括在极端条件下的交互式网站材料的设计。短脉冲激光照射引起的超快材料现象的一般概念的非技术描述将通过该程序中获得的研究结果说明，并以图像，计算机动画和简单的交互式模拟的形式介绍。