Computation of Grain Boundary Energy Landscapes as a Tool for Grain Boundary Engineering

晶界是金属和陶瓷中的缺陷，通常控制腐蚀和开裂等失效机制。然而，在给定的材料试样中发现了大量不同的晶界类型。通过晶界工程控制材料中存在的晶界类型，可以实现材料性能的显著增强，包括耐腐蚀性和抗开裂性。该项目的目的是通过研究不同类型晶界的特性来推进晶界工程领域，以确定哪些晶界在防止或导致材料失效方面最重要。为了实现这一点，各种不同类型的晶界进行了研究，使用一种计算方法称为激活-弛豫技术。该方法提供了关于晶界的动力学性质的基本信息，晶界的动力学性质本质上与材料降解和失效的机制相关。 本文的研究成果将推动晶界工程领域的发展。告诉材料设计师材料结构中最关键的缺陷是什么，使他们能够专注于消除这些关键缺陷，从而延长各种工程材料的寿命。因此，在微观结构水平上的材料设计工具箱将大大增加，在减少材料失效，提高产品可靠性，从而减少材料使用方面具有社会效益。该项目还侧重于培养博士-水平的专家和学士学位-微观结构设计最新工具的高级从业者。 再加上研究对工业问题的重大影响，这些新培训的学生准备将研究成果带入该领域，并在先进材料技术中实施。

Grain boundaries are defects in metals and ceramics that often control failure mechanisms such as corrosion and cracking. However, a vast number of different grain boundary types are found in a given material specimen. By controlling the types of grain boundaries present in a material through a process called grain boundary engineering, dramatic enhancements in materials performance, including corrosion and cracking resistance, can be achieved. The aim of this project is to advance the field of grain boundary engineering by investigating the properties of different types of grain boundaries in order to determine which grain boundaries are most important in preventing or causing materials failure. To accomplish this, a variety of different types of grain boundaries are investigated using a computational method called the activation-relaxation technique. This method provides essential information regarding the kinetic properties of grain boundaries, which are inherently related to the mechanisms of material degradation and failure. The research results produced in this work will advance the field of grain boundary engineering?telling materials designers what the most critical defects in a material structure are allows them to focus on removing those critical defects, thereby extending the lifetime of a variety of engineering materials. The toolbox for materials design at the microstructural level will thus be greatly augmented, with societal benefits in reducing materials failures, enhancing product reliability, and thereby reducing materials usage. The project also focuses on the training of Ph.D.-level experts and B.S.-level practitioners in the newest tools of microstructure design. Combined with significant exposure of the research to industrial concerns, these newly-trained students are poised to carry the research results into the field and effect their implementation in advanced materials technologies.