Different Connection Models of Icosahedral Structures in TiAl Alloy Caused by the Cooling Rates. Issue 12 (13th October 2021)

• Record Type: Journal Article
• Authors: Liu, Zhen; Li, Lianxin; Gao, Tinghong; Xie, Quan; Chen, Qian; Liang, Yongchao; Tian, Zean; Wang, Bei
• Is Part Of: Physica status solidi. Volume 258:Issue 12(2021)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2021-10-13
• Subjects: connection models -- icosahedral structures -- metallic glass -- molecular dynamics simulation -- short-range order; Solid state physics -- Periodicals; Solids -- Periodicals; Atomic structure -- Periodicals; 530.41
• DOI: 10.1002/pssb.202100083
• Languages: English
• ISSNs: 0370-1972

Abstract

Abstract : High‐quality TiAl alloy is used to fabricate aerospace equipment with excellent mechanical properties because of its interesting properties, including low density, high specific yield strength, and better corrosion resistance. However, the fabrication of high‐quality TiAl alloy is challenging because the connection mechanism between different types of clusters in TiAl alloy during the rapid cooling process is not clear. This study uses molecular dynamics (MD) simulation methods to study the connection models of icosahedral (ICO) structures and other defective ICO structures at different cooling rates. The ICO structures represent the short‐range ordered structure in the system. Moreover, the complex connections between the ICO and its defective structures constitute the basic structural features of TiAl metallic glass. The results show that the connections between ICO and its defective structures differ significantly with the cooling rate. It is easier to form a more complex nanostructure connected by the ICO structures with higher proportion of Al central atoms at the lower cooling rate. As the temperature drops at the same rate, the number of Al central atoms with smaller atomic radius in the icosahedrons increases gradually, giving them an absolute advantage. Abstract : TiAl alloys form metallic glass under the rapid solidification, and the connections between icosahedral (ICO) polyhedrons and others are considered to be the main structure in metallic glass. Herein, the molecular dynamics simulation method is used to study the connection models of ICO polyhedrons with other polyhedrons in TiAl alloy at four different cooling rates.