Dynamic probing of structural evolution for Co₅₀Ni₅₀ metallic glass during pressurized cooling using atomistic...

In this study, firstly favorable glass-forming composition for the binary Co-Ni alloy is identified as Co₅₀Ni₅₀ based on statistically evaluated thermodynamic parameters such as mixing enthalpy (∆H_mix), mixing entropy (∆S_mix), and topological parameter such as atomic size difference (δ). Secondly, molecular dynamics (MD) simulations have been performed to investigate the glass-forming ability (GFA) and cluster evolution during the rapid solidification (7.67 K/ps) of Co₅₀Ni₅₀ under hydrostatic pressure (0, 0.25, 0.50, 1, 1.25, 2, 3, 5 GPa). It has been observed that with increasing pressure, glass transition temperature (T_g) also increases thereby increasing the GFA of Co₅₀Ni₅₀. Moreover, Voronoi cluster analysis reveals that quasi-icosahedral type clusters such as <0281> and <0282>, mixed types of cluster such as <0363>, <0364>, <1254>, and <0372> and crystal type clusters such as <0443> and <0444> have maximum population among the other clusters at different pressures at Co as well as Ni-centered atoms.