  We applied an efficient methodology to separate vibrational and
configurational entropies in bulk metallic glasses by means of molecular
dynamics simulation based on a combination of non-equilibrium adiabatic
switching and reversible scaling methods. This approach involves calculating
the vibrational free energy using the Einstein crystal as a reference for the
solid phase and the recently proposed Uhlenbeck-Ford model for the fluid phase.
This methodology has the advantage that it does not require a crystalline solid
phase for separating the entropies. Therefore, in principle, it is applicable
to any material, regardless of whether or not it has a crystalline phase. Using
this methodology, we separate the vibrational and configurational entropies of
two metallic glasses with different fragilities at zero external pressure,
namely, Cu$_{50}$Zr$_{50}$ and Cu$_{46}$Zr$_{46}$Al$_{8}$. We find that the
results for the former alloy are in quite reasonable agreement with recent
experimental work by Smith \textit{et al.}[H. L. Smith \textit{et al.}, Nat.
Phys. \textbf{13}, 900 (2017)]. We also find the configurational entropy of the
glass containing Al to be 70\% larger than that of the other glass. Our results
suggest that, although other factors may be at play, the configurational
entropy can be used to investigate the effect of the addition of a
minor-alloying element on the glass-forming ability of bulk metallic glasses.
