Three-dimensional Surface Corrosion Growth Model for Materials Design

21世纪的建筑材料必须满足日益苛刻的性能和寿命标准。结构部件的强度和完整性劣化的主要原因是腐蚀和疲劳以及结构材料中的其他失效机制。在腐蚀的各个方面中，点蚀是一个复杂的过程，是许多工程行业面临的主要问题。点蚀机理通常始于微/纳米结构水平，具体机理取决于材料组成、电解液等环境条件。尽管多年来人们对腐蚀引起的材料损失进行了大量的研究，但对点蚀引起的力学特性及其在多个层次上的关系尚不清楚。为了更好地理解和设计耐腐蚀材料，材料损失信息以及不同材料尺度上的拓扑结构及其相互关系是必要的。本研究的目的是建立一个三维腐蚀生长模型，以帮助评估和设计材料及其对结构完整性的影响。腐蚀生长模型将基于元胞自动机方法发展为离散动力系统。该方法将腐蚀过程的宏观尺度(腐蚀点分布和材料损失)和微观尺度(化学作用机理)结合到模型中。在建立腐蚀增长模型时，将使用涉及物理和机械基础的机制来获取规则。开发的模型将通过与印第安纳州克雷恩部门的海军水面作战中心合作，以及从德克萨斯州雷神系统公司获得的数据，使用真实数据进行测试和验证。将开发三维可视化软件，实时可视化腐蚀增长数据，查看腐蚀增长过程。通过该项目开发的算法将直接用于工程和计算机科学学科中的材料和模拟课程，所提出的研究将大大有助于了解材料中的腐蚀生长过程。三维可视化能力将有助于更好地了解腐蚀增长过程的特征，并可能导致开发更有效的腐蚀增长和预测算法。对基于当地规则的宏观和微观腐蚀增长模型的基本理解将为设计各种工程应用的耐蚀材料提供有价值的信息和工具。建议的方法将为材料中的结构腐蚀提供一个通用的解决方案，以便它可以扩展到其他结构材料。

0116047PidapartiStructural materials of the 21st century will have to meet increasingly demanding standards for performance and life. The strength and integrity of a structural component deteriorates mainly due to corrosion and fatigue along with other failure mechanisms in structural materials. Among various aspects of corrosion, pitting corrosion is a complex process, and is a major problem in many engineering industries. Pitting corrosion mechanism usually initiate at the micro/nano-structure level and the details of the mechanisms depend on the material composition, electrolyte and other environmental conditions. Even though much effort has been put into assessing the material loss due to corrosion over the years, the mechanical characteristics and its relationship at multiple levels due to pitting corrosion are not yet known. The material loss information along with the topology and its relationship at various material scales are necessary for better understanding and designing of corrosion resistant materials.The objective of the proposed research is to develop a three-dimensional corrosion growth model to aid in the assessment and design of materials and their effect on structural integrity. Corrosion growth model will be developed as a discrete dynamical system based on cellular automata approach. This approach incorporates both macroscopic (corrosion pit distribution and the material loss) and microscopic (chemical interaction mechanisms) scales of the corrosion process into the model. Mechanisms involving both physical and mechanistic basis will be used to obtain rules in developing corrosion growth models. The developed models will be tested and validated using real data by collaborating with Naval Surface Warfare Center, CRANE division, Indiana, and with the data obtained from Raytheon Systems Company, Texas. A three-dimensional visualization software will be developed to visualize the corrosion growth data in real time to see the corrosion growth process. Algorithms developed through this project will be directly used in materials and simulation courses in Engineering and Computer Science disciplines.The proposed research will greatly help to understand the corrosion growth process in materials. The 3D visualization capability will provide insight into better understanding of the characteristics of corrosion growth process, and may lead to the development of more efficient corrosion growth and prediction algorithms. A fundamental understanding of the macro- and micro-level corrosion growth models based on local rules will provide valuable information and tools for designing corrosion resistant materials for a variety of engineering applications. The proposed approach will provide a general solution to structural corrosion in materials so that it can be scaled up to other structural materials.