Molecular dynamics study of short range order and viscosity to understand the glass forming ability in Fe_XZr_(100-X) metallic glasses

摘要

We have performed molecular dynamics simulations on binary Fe_XZr_(100-X) (X = 88, 90) system to understand the glass forming ability by evaluating the short range order and viscosity. Our analysis has shown that in FeZr system the addition of Zr has enhanced the percentage of Fe centred <0,1,10,2> and <0,0,12,0> clusters. The evolution of Fe center clusters has played an important role in local structural transition along with other equally significant Zr-centered <0,3,6,4> and <0,2,8,4> clusters. Moreover, the viscosity was calculated from Green-Kubo approach and fragility parameter (m) was obtained by Vogel-Fulcher-Tammann (VFT) relation by measuring the slope of a logarithm of the viscosity versus temperature. The obtained value of m for both the system was found in agreement with the reported values m of the good glass former. From this, it may be suggested that Fe centered clusters influence the packing density of the glass and lower the m value which then leads an alloy to show better GFA.