Why Grain Growth is Not Curvature Flow

Abstract

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.

11 pages, 5 figures. Supplementary Information attached (additional 7 pages, 5 figures)

References in corpus (5)

• Grain-Boundary Kinetics: A Unified Approach
• Grain Boundary Shear Coupling is Not a Grain Boundary Property
• Grain growth beyond the Mullins model, capturing the complex physics behind universal grain size distributions
• A Continuum Multi-Disconnection-Mode Model for Grain Boundary Migration
• Interface Faceting-Defaceting Mediated by Disconnections

Cited by in corpus (3)

• Disconnection formation via segregation-induced grain boundary phase transitions
• Understanding the kinetics of static recrystallization in Mg-Zn-Ca alloys using an integrated PRISMS simulation framework
• Solid-State Dewetting of Polycrystalline Thin Films: a Phase Field Approach