On the miscibility gap in tungsten-based alloys

TL;DR

This paper develops a statistical physics-based approach to model the miscibility gaps in tungsten alloys, accurately incorporating various entropy contributions and validating results with experimental data.

Contribution

It introduces a comprehensive method combining first-principles calculations and entropy analysis to predict alloy miscibility gaps, including new alloy stabilization insights.

Findings

Accurate modeling of tungsten-chromium and tungsten-molybdenum miscibility gaps.

Agreement with experimental data for the modeled systems.

Proposed alloy modifications with tantalum and hafnium to enhance stability.

Abstract

In this work we establish an approach to model miscibility gaps of alloys using statistical physics, lattice dynamics from first-principles calculations. We carefully calculate the entropy to include all processes introducing disorder to the system, i.e., combining the electronic, phononic, and configuration entropies. Furthermore we present our algorithm for generating Special Quasirandom Structures (SQS). We model the miscibility gap in tungsten - chromium and tungsten - molybdenum systems, obtaining the agreement with the experimental data. Furthermore, we propose an enhancement for the tungsten-chromium W$_{70}$Cr$_{30}$ alloy with tantalum and hafnium, leading to the modified stabilization temperatures $T_S$, where the solid solution is miscible.