講座題目：Dynamics of Grain Boundaries Based on Underlying Microstructures

主講人：項陽  教授

事情單位：Hong Kong University of Science and Technology

講座時間：2024年7月3日（周三）15：30-17：00

講座地點：清水河校區六號科研樓A344

主講人簡介：项阳，香港科技大学数学系教授，港深协同创新研究员机械学习和自动驾驶算法研究实验室卖力人。现任东亚工业与应用数学学会主席。主要研究偏向是盘算数学，机械学习理论及应用，应用领域包罗质料科学和人工智能等前沿偏向。项阳教授在与缺陷相关的质料结构建模与盘算和基于深度神经网络的高性能盘算上取得了一系列具有重要意义的原创性结果。项阳教授是2021年美国工业与应用数学协会(SIAM)质料科学中数学问题聚会会议大会陈诉人，入选斯坦福大学宣布的全球TOP 2%科学家。

講座內容：Grain boundaries are the interfaces between grains with different orientations in polycrystalline materials. Energetic and dynamic properties of grain boundaries play essential roles in the mechanical and plastic behaviors of the materials. These properties of grain boundaries strongly depend on their microscopic structures. We present continuum models for the energy and dynamics of grain boundaries based on continuous distributions of the line defects (dislocations or disconnections) on them.  The long-range elastic interaction between these line defects is included in the continuum models. The continuum models are able to describe the shear coupling motions of grain boundaries, which were observed in atomistic simulations and experiments and cannot be explained by the classical motion by mean curvature models. We further present a unified continuum model based on variational framework to account for all these microscopic mechanisms.