Ex Situ Observation of Microstructure Evolution During Abnormal Grain Growth in Aluminum Alloy

Abstract

The sequential microstructural evolution of abnormal grain growth in the aluminum alloy was traced by ex situ observation using electron-backscattered diffraction during secondary recrystallization. Near the growth front of abnormally growing grains, many three- or four-sided grains with a negative curvature, which had the same orientation as abnormally growing grains, were penetrating the surface, indicating that abnormal grain growth occurs dominantly by repeated events of triple-junction wetting. Also, abnormally growing grains were shown exclusively to have sub-boundaries.