Why grain growth is not curvature flow

• 成果类型: Article
• 署名作者: Qiu, Caihao; Srolovitz, David J.; Rohrer, Gregory S.; Han, Jian; Salvalaglio, Marco
• 署名单位: City University of Hong Kong; University of Hong Kong; University of Hong Kong; Carnegie Mellon University; Technische Universitat Dresden; Technische Universitat Dresden
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-12446
• DOI: 10.1073/pnas.2500707122
• 发表日期: 2025-06-17
• 关键词: boundary motion; thin-films; mechanisms; stagnation; rotation; energy; models

摘要

Grain growth in polycrystals is traditionally considered a capillarity-driven process, where grain boundaries (GBs) migrate toward their centers of curvature (i.e., mean curvature flow) with a velocity proportional to the local curvature (including extensions to account for anisotropic GB energy and mobility). Experimental and simulation evidence shows that this simplistic view is untrue. We demonstrate that the failure of the classical mean curvature flow description of grain growth mainly originates from the shear deformation naturally coupled with GB motion (i.e., shear coupling). Our findings are built on large-scale microstructure evolution simulations incorporating the fundamental (crystallography-respecting) microscopic mechanism of GB migration. The nature of the deviations from curvature flow revealed in our simulations is consistent with observations in recent experimental studies on different materials. This work also demonstrates how to incorporate the mechanical effects that are essential to the accurate prediction of microstructure evolution.