Glass forming ability and thermal stability of (ZrTiHfNi)100-xNbx high entropy amorphous alloy

Abstract

In this study, (ZrTiHfNi)_100-xNb_x high entropy amorphous alloy was successfully prepared by arc melting and single roller melt spinning. As the Nb content was increased, the entropy of high entropy amorphous alloys gradually increased, the thermal stability steadily improved, and the crystallization temperature increased. The Nb20 system demonstrated the highest entropy value and best thermal stability, but its glass forming ability (GFA) was weaker than that of the Nb15 system. Compared with traditional amorphous alloys, high entropy amorphous alloys showed better thermal stability, but reduced GFA. In addition, this study highlighted the unusual correlation between the GFA and the thermal stability of high entropy amorphous alloys, focusing on the entropy. Due to the high entropy, the atoms in high entropy amorphous alloys diffuse slowly during heating, resulting in slow crystallization kinetics and high thermal stability. Furthermore, due to the dominance of the kinetic mechanism over the thermodynamic mechanism, the amorphous forming ability of high entropy amorphous alloys decreased.