Short range order and stability of a mechanically alloyed Cr25Nb75 glass determined by total scattering and first principles

The atomic environment and stability of an amorphous Cr25Nb75 alloy was studied on the basis of average atomic coordination, average cluster number density as well as cluster radial distribution of these quantities based on Reverse Monte Carlo fitting of multiple total scattering datasets. A number of the most representative clusters of the RMC supercell were isolated and relaxed via Density Functional Theory. Average coordination of both Cr and Nb atoms was similar, possibly due to the similarity of their covalent radii. Also, the histograms of average coordination of both species suggested binomial distributions, possibly reflecting two separate modes of atomic bonding. Cr-centered clusters were found to be more cohesive than Nb-centered ones and overall cluster stability appeared to be correlated to minority Cr valence populations.