  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.
