Structural Origin of Enhanced Stability of Ni-Nb Ultrastable Metallic Glass

Abstract:

Molecular dynamics simulations were used to simulate the vapor deposition process for the investigation of the structural evolution of Ni-Nb metallic glasses as a function of substrate temperature. Results show that optimal substrate temperature is approximately 850 K, at which the glass attains the lowest potential energy and thus the highest stability. The formation of ultrastable glass is accompanied by a transition of short-range ordered structure from a distorted icosahedron to a perfect icosahedron. This phenomenon can be further confirmed in Mg-Cu-Y, La-Ni-Al, Zr-Cu-Al, and Cu-Zr metallic glass systems. In this research, the structural origin of ultrastable metallic glass formation is established, providing new insights into the nature of the glass transition.