Development of a Phase Field Tool Coupling With Thermodynamic Data for Microstructure Evolution Simulation of Alloys in Nuclear Reactors

Yaolin Guo,Shiyu Du,Jiexi Song,Biao Zhang,Diwei Shi,Yifan Li,Moran Bu,Zhen Liu

doi:10.3389/fmats.2021.627864

Yaolin Guo, Shiyu Du + Show 6 more

Open Access

https://doi.org/10.3389/fmats.2021.627864

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Abstract

We have developed a new phase field tool PHAFIS to automatically incorporate the thermodynamic data for both of WBM and KKS phase field simulations, which are widely used in the simulation of microstructure evolution of nuclear materials. Based on the generic C/C++ programming language, PHAFIS is capable of automatically parsing the standard TDB files, extracting the free energy and diffusion potential varying with the composition in an analytical way. Based on the two diffrerent TDB files of Fe-Cr binary system and the interpolated data, the phase morphologies during spinodal decomposition at 700 K and liquid-solid transition at high temperatures above 1800 K are reproduced and compared with each other by WBM and KKS model, respectively. Specifically, both of interface-controlled and diffusion-controlled phase transition mechanisms are successfully revealed for solidification through our KKS simulation, consistent with classic phase transition theories. It can be concluded that even slight differences in thermodynamic data will cause significant changes in the microstructure evolution. The integrity of our software tool will facilitate the coupling of phase field methods with thermodynamic data for other materials, paving a fundamental step for coupling more factors required in microstructure simulation.

Highlights

After the Fukushima nuclear accident, nuclear safety issues made the importance of the materials in the reactor prominent, which is likely to be tackled in the concept of accident tolerant fuel (ATF) (Zinkle and Was, 2013)
It is capable of parsing the standard thermodynamic database” (TDB) file format, extracting the mathematical expression of all phases, calculating accurately the free energy and the 1st derivative with respect to solute concentration at a given temperature, and interpolating the free energy to accelerate phase field simulation
We will start with the basic syntax and structure of standard TDB format, establish the data structure for the free energy of a phase according to the sublattice solution model, and incorporate the thermodynamic data into the phasefield models

Summary

INTRODUCTION

After the Fukushima nuclear accident, nuclear safety issues made the importance of the materials in the reactor prominent, which is likely to be tackled in the concept of accident tolerant fuel (ATF) (Zinkle and Was, 2013). Thermodynamic Coupling Phase Field Program materials methodology such as multi-scale simulations and big data methods. Apart from kinetic parameters, for the WBM model, the bulk free energy of the phases and their first derivatives with respect to solute concentration should be derived from thermodynamic data, on the basis of Eq (1). It is capable of parsing the standard TDB file format, extracting the mathematical expression of all phases, calculating accurately the free energy and the 1st derivative with respect to solute concentration at a given temperature, and interpolating the free energy to accelerate phase field simulation. PHAFIS and our existing solving modules for phase field models can be seamlessly connected, laying a foundation for accurate calculation of true material systems

INCORPORATION PROCEDURE OF TDB FILES

Findings

DATA AVAILABILITY STATEMENT