Experimental investigation of the local environment and lattice distortion in refractory medium entropy alloys

TL;DR

This study uses EXAFS analysis to examine local environments and lattice distortions in refractory medium entropy alloys, revealing atomic-scale mixing, structural distortions, and quantifying static disorder.

Contribution

It provides experimental insights into local atomic arrangements and lattice distortions in refractory medium entropy alloys using EXAFS analysis.

Findings

Good atomic-scale mixing observed in alloys

Structural distortions indicated by distance distributions

Quantification of static disorder correlating with lattice distortion

Abstract

EXAFS analysis of pure elements, binary and ternary equiatomic refractory alloys within the Nb-Zr-Ti-Hf-Ta system is performed at the Nb and Zr K-edges to analyze the evolution of the chemical local environment and the lattice distortion. A good mixing of the elements is found at the atomic scale. For some compounds, a distribution of distances between the central atom and its neighbors suggests a distortion of the structure. Finally, analysis of the Debye-Waller parameters show some correlation with the lattice distortion parameter $\delta ^2$, and allows to quantify experimentally the static disorder in medium entropy alloys.