Role of Grain Boundaries under Long-Time Radiation

Area of Science:

• Materials Science
• Nuclear Engineering
• Condensed Matter Physics

Background:

• Grain boundaries are crucial for radiation resistance in structural materials.
• Understanding the long-term impact of radiation-induced microstructural changes at grain boundaries is essential.
• Current models lack a detailed connection between grain boundary behavior and macroscopic material properties under irradiation.

Purpose of the Study:

• To develop a coarse-grained model for predicting the long-time morphological evolution of grains under irradiation.
• To establish a link between grain boundary microstructure and point defect absorption.
• To investigate the influence of point defects on grain boundary dynamics and material stability.

Main Methods:

• Formulation of a coarse-grained model using a jump Robin-type condition for point defect absorption at interfaces.
• Development of a concise formula relating the sink strength of polycrystalline aggregates to grain size.
• Implementation of simulations for coupled evolution of grain boundaries and point defects.

Main Results:

• The model accurately predicts the relationship between sink strength and grain size, aligning with experimental data.
• Simulations show that internal point defect sources accelerate grain shrinking.
• Radiation exposure promotes the extension of twin boundary segments within the material.

Conclusions:

• The developed coarse-grained model provides a framework for understanding irradiation-induced microstructural evolution at grain boundaries.
• The findings highlight the significant role of point defect dynamics in material degradation and morphological changes.
• This research contributes to the design of advanced radiation-resistant materials for long-term applications.