On the origin of non-Arrhenius behavior of grain growth

TL;DR

This study investigates the fundamental mechanisms of non-Arrhenius grain growth in polycrystalline materials, revealing it as a thermally activated process influenced by temperature-dependent and independent factors, with a transition to Arrhenius behavior at higher temperatures.

Contribution

The paper introduces a new grain growth model and provides experimental and theoretical evidence clarifying the thermally activated nature of non-Arrhenius grain growth.

Findings

Non-Arrhenius grain growth is thermally activated without a specific characteristic temperature.

The behavior is controlled by interplay between temperature-dependent and independent factors.

Transition from non-Arrhenius to Arrhenius behavior occurs at higher temperatures.

Abstract

Non-Arrhenius grain growth has been observed in a range of polycrystalline materials; however, its fundamental mechanisms, particularly whether the process is thermally activated or exhibits anti-thermally activation, remain controversial. In this study, SrTiO3 was employed as a model system to systematically investigate non-Arrhenius grain growth behavior through combined experimental and theoretical approaches, utilizing a newly developed grain growth model. The results reveal that non-Arrhenius grain growth is a thermally activated process without a definitive characteristic temperature, which is primarily controlled by the interplay between temperature-dependent factors and the temperature-independent parameters such as grain size and its distribution. Moreover, during abnormal grain growth (AGG), the non-Arrhenius behavior of grain growth primarily occurs at lower temperatures and gradually transitions to Arrhenius-type behavior as the temperature increases.