Phase Field Modelling of Abnormal Grain Growth

Area of Science:

• Materials Science
• Physics

Background:

• Heterogeneous grain structures arise from abnormal grain growth during polycrystalline material processing.
• Controlling grain structure is crucial for practical applications, necessitating a deeper understanding of growth mechanisms.

Purpose of the Study:

• To systematically evaluate conditions for abnormal grain growth initiation using phase field modeling.
• To classify grain boundaries based on mobility and analyze their impact on grain structure heterogeneity.

Main Methods:

• Utilized phase field modeling to simulate grain growth in 2D.
• Classified grain boundaries into high- and low-mobility types based on disorientation angle and grain type interactions.
• Investigated three scenarios: critical threshold angle, two grain types (A, B), and three grain types (A, B, C).

Main Results:

• Quantified the influence of mobility ratio, threshold angle, and grain type fractions on abnormal grain growth.
• Determined the mobility ratios required for abnormal grain growth as a function of high-mobility boundary fraction.
• Identified the three-grain-type scenario (A, B, C) as promoting irregular abnormal grains and island formation.

Conclusions:

• Phase field modeling provides a robust framework for understanding abnormal grain growth.
• Grain boundary mobility and type distribution significantly influence the resulting grain structure heterogeneity.
• The three-grain-type model effectively replicates experimentally observed complex abnormal grain structures.