Evolution of phase morphologies, compositions, structures of Mg-Y-Nd system with Sm addition

• Published in: Results in physics Vol. 11; pp. 152 - 157
• Main Authors: Jia, Guilong, Guo, Erjun, Wang, Liping, Feng, Yicheng, Chen, Yanhong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.12.2018; Elsevier
• Subjects: Mg-Y-Nd-Sm-Zr; Phase evolution; TEM; Phase evolution; Mg-Y-Nd-Sm-Zr; TEM
• ISSN: 2211-3797; 2211-3797
• DOI: 10.1016/j.rinp.2018.08.042

In this study, the evolution of phase morphologies, compositions, structures of Mg-Y-Nd system with Sm addition were investigated. The microstructure of the as-cast alloy consists of a Mg-matrix, Mg24Y5 (bcc structure, a = 1.1250 nm), and Mg5(Y0.7Nd0.1Sm0.2) (fcc structure, a = 2.2472 nm) phases. After a solution treatment, the eutectic phases are substantially dissolved into the Mg-matrix. A large amount of β′ precipitates are dispersed and precipitated in the grain after a T6 heat treatment, and the orientation relationships between β′ precipitates and Mg-matrix are (001)β′ || (0001)Mg, (020)β′ || (101¯0)Mg, [100]β′ || [011¯0]Mg. Furthermore, the quadrate phases indexed as Mg6Y3(Nd0.8Sm0.2)1, Mg6Y3(Nd0.2Sm0.8)1, and Mg10Y5(Nd0.2Sm0.8)1 are observed in various heat treatment states, which are fcc structures and their lattice parameters are a = 0.5318 nm, a = 0.5319 nm, a = 0.9894 nm, respectively.