Predicting the glass-forming ability of rare earth-contained Fe-based alloys by features of dynamic transition in their melts

• Published in: Journal of non-crystalline solids Vol. 537; p. 120020
• Main Authors: Zhao, Yunbo, Bai, Yanwen, Ding, Yijun, Hu, Lina
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.06.2020
• Subjects: Fe-based metallic glasses; Glass-forming ability; Liquid fragility; Rare earth element; Viscosity; Viscosity; Rare earth element; Glass-forming ability; Liquid fragility; Fe-based metallic glasses
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2020.120020

•A dynamic transition has been found to generally exist in Fe-based melts well above their liquidus temperatures.•The dynamic transition becomes indistinct with minor addition of rare earth element into the Fe-based melts.•A negative correlation between the degree of dynamic transition in melts and the glass-forming ability has been established in Fe-based alloys.•A scenario of microstructural evolution in melts has been built to explain this correlation. In this work, we firstly focus on the features of dynamic behaviors of two rare earth-contained alloy systems Fe-B-(Nb)-Y and Fe-(Co)-Cr-Mo-C-B-Y well above their liquidus temperatures. Compared with a relatively distinct viscosity discontinuity observed in the Fe-based melts without rare earth elements, such discontinuity becomes indistinct. However, analysis on the detected viscosity data indicates a dynamic crossover still exists in both of the two alloy systems. Using the parameter F representing the degree of the dynamic transition during cooling, the feature of the dynamic transition in these two alloy systems has been quantified and the negative correlation of F and the glass-forming ability (GFA) has been observed. A scenario of microstructural evolution has been built to explain this correlation. This work sheds light on controlling the GFA of rare earth-contained Fe-based alloys from the viewpoint of the melt dynamics, which belongs to the long-term standing issue of the liquid-solid inheritance.