Revealing the key structural characteristics governing the glass forming ability in Ca50Mg50-xZnx alloys

• Published in: Journal of non-crystalline solids 2023-09, Vol.616, p.122442, Article 122442
• Main Authors: Han, Lei, Liang, Yong-chao, Fan, Lang-tao, Mo, Yun-fei, Tian, Ze-an, Wang, Cun-jing, Zhou, Li-li
• Format: Article
• Language: English
• Subjects: CaMgZn alloy; Glass forming ability; Molecular dynamics simulation; Rapid solidification; Topologically close-packed cluster
• ISSN: 0022-3093; 1873-4812
• DOI: 10.1016/j.jnoncrysol.2023.122442

•Increased Zn content enhances the glass forming ability (GFA) of Ca50Mg50-xZnx.•Topologically close-packed cluster is essential structure governing the GFA.•S433 acts as a structural signal of the start of the phase transition.Finding out the key structural characteristic that determines the glass transition is important for improving the glass forming ability (GFA) of metal melts. In this paper, the rapid solidification processes for five Ca50Mg50-xZnx (x = 15, 20, 25, 30, 35) ternary alloys are calculated by molecular dynamics simulations. Results indicate that the GFA increases monotonically with the increase of Zn content, and the system with higher Zn content has lower average atomic potential energy. Moreover, rather than the icosahedron, the topologically close-packed (TCP) cluster much more comprehensively describes the key structural characteristics of metallic glasses. The addition of Zn promotes the formation of TCP-type structures that with higher local packing density so as to enhance the GFA of the system. In addition, the evolution of the population of S433 highlights the start temperature Tx of the phase transition. These findings provide new understanding of the glass transition of metal melts.