Experimental and Theoretical Studies on Composition Limits of Metallic Glass Formation in the Ni-Mo System

The Ni-Mo system was selected as a model system to study the composition limits of metallic glass formation by ion mixing experiments as well as by molecular dynamics simulation. The 200keV xenon ion mixing was conducted for ten Ni-Mo mutilayered samples with various concentrations and the results showed that the glass-forming composition range was 39.8-80.4at.% Mo, which is in good agreement with the assessment from an empirical model. Through comparing the stability of the Ni-rich and Mo-rich solid solutions with various concentrations versus their amorphous counterparts, two critical supersaturated solid solubilities were found by molecular dynamics simulation to be 21 at.% Mo in Ni and 25at.% Ni in Mo, from which the glass forming range was deduced to be within 21-75 at.% Mo. The correlation of the simulated glass-forming range with those obtained by ion irradiation and solid-state reaction is also discussed.