# Simulations of grain growth in tungsten armor materials under ARC plasma edge operation conditions using an integrated plasma-edge/materials model

## TL;DR

This paper presents a new integrated model to simulate grain growth in deuterium-exposed tungsten under plasma conditions, revealing rapid grain growth near plasma and stability inside the material, with implications for tungsten's use in fusion reactors.

## Contribution

The study introduces a two-dimensional vertex dynamics model fitted to atomistic data for simulating grain growth in tungsten under plasma exposure, a novel approach for this application.

## Key findings

- Fast grain growth occurs near plasma at 1400 K within 100 seconds.
- Microstructure remains stable deep inside the material at 1000 K over several days.
- Conventional tungsten is highly susceptible to grain growth above 1000 K.

## Abstract

An integrated model of grain growth deuterium-exposed tungsten polycrystals, consisting of a two-dimensional vertex dynamics model fitted to atomistic data, has been developed to assess the grain growth kinetics of deuterium-exposed polycrystalline tungsten (W). The model tracks the motion of grain boundaries under the effect of driving forces stemming from grain boundary curvature and differential deuterium concentration accumulation. We apply the model to experimentally-synthesized W polycrystals under deuterium saturated conditions consistent with those of the ARC concept design, and find fast grain growth kinetics in the material region adjacent to the plasma (at 1400 K, <100 seconds for full transformation), while the microstructure is stable deep inside the material (several days to complete at a temperature of 1000 K). Our simulations suggest that monolithic W fabricated using conventional techniques will be highly susceptible to grain growth in the presence of any driving force at temperatures above 1000 K.