主講人：美國國家工程院院士 David Srolovitz教授

時間：2023年5月31日14：00

地點：北京科技大學 學術報告廳

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

David Srolovitz院士簡介：

David Srolovitz教授發表了約550篇關于材料理論和晶體缺陷模擬、微觀結構、變形、薄膜生長、相變、熱力學以及相關研究方法的論文，h指數為105，獲得40000余次引用。他是美國國家工程院院士，MRS、TMS、ASM、IOP會士，也是MRS材料理論獎的得主；曾是普林斯頓大學、賓夕法尼亞大學和香港城市大學等知名大學的教授，在材料科學、機械工程、航天工程、計算機科學和物理學等領域擔任過教職。目前的研究興趣集中在材料界面的結構、熱力學、動力學等性質、位錯、晶粒生長以及這些缺陷對材料的力學行為、光電性質和輻照損傷的影響；開發了第一性原理、原子尺度、缺陷動力學、微觀結構和連續介質模型的材料模擬新技術以及多尺度模擬方法。

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.