主讲人：美国国家工程院院士 David Srolovitz教授

时间：2023年5月31日14：00

地点：北京科技大学 学术报告厅

题目：A General Approach to Interfaces in Crystalline Solids: Precipitate morphology, microstructure evolution, and dislocation-interactions

David Srolovitz院士简介：

David Srolovitz教授发表了约550篇关于材料理论和晶体缺陷模拟、微观结构、变形、薄膜生长、相变、热力学以及相关研究方法的论文，h指数为105，获得40000余次引用。他是美国国家工程院院士，MRS、TMS、ASM、IOP会士，也是MRS材料理论奖的得主；曾是普林斯顿大学、宾夕法尼亚大学和香港城市大学等知名大学的教授，在材料科学、机械工程、航天工程、计算机科学和物理学等领域担任过教职。目前的研究兴趣集中在材料界面的结构、热力学、动力学等性质、位错、晶粒生长以及这些缺陷对材料的力学行为、光电性质和辐照损伤的影响；开发了第一性原理、原子尺度、缺陷动力学、微观结构和连续介质模型的材料模拟新技术以及多尺度模拟方法。

摘要：

Since single crystals are rare, interfaces are inherent features of almost all natural and engineering materials. Their behavior determine a wide range of material properties. This includes both homo-phase (grain boundaries) and hetero-phase (multiphase materials). Most interface properties are, unsurprisingly, related to their structures. I will first present a general description of interfaces and their defects-based on some simple crystallographic ideas. The most important interface defects are disconnections; line defects with both dislocation and step character. Next, I will use these ideas to generalize the famous Frank-Bilby equation, to predict orientation relationships (ORs) between matrixes and precipitates; i.e., relative orientations of two crystalline phases and interface orientations. I will then describe how to go from a disconnection picture of interface migration to continuum descriptions of microstructure evolution (interface faceting, precipitate morphology evolution, and grain growth). Finally, I will analyze how dislocations in bulk phases interact with interfaces including dislocation blocking (Hall-Petch behavior), absorption, reflection, transmission and interface sliding. Comparison with experimental observations will be made throughout.