Thermodynamic assessment of Mg-Ni-Y system focusing on long-period stacking ordered phases in the Mg-rich corner

作     者：Cheng Liu Qun Luo Qin-Fen Gu Qian Li Kuo-Chih Chou 

作者机构：State Key Laboratory of Advanced Special Steels&Shanghai Key Laboratory of Advanced FerrometallurgySchool of Materials Science and EngineeringShanghai UniversityShanghai 200444China Australian SynchrotronClayton 3168Australia 

出 版 物：《Journal of Magnesium and Alloys》 (镁合金学报（英文）)

年 卷 期：2022年第10卷第11期

页      面：3250-3266页

核心收录：

学科分类：08[工学] 080502[工学-材料学] 0805[工学-材料科学与工程（可授工学、理学学位）] 

基　　金：financially supported by the National Natural Foundation China (51671118 and 51871143) the Science and Technology Committee of Shanghai Municipality(19010500400) the “Chenguang” Program from the Shanghai Municipal Education Commission (17CG42) 

主　　题：LPSO phases Crystal structures Phase equilibria Thermodynamics 

摘      要：The long-period stacking ordered phases(LPSOs) in Mg-Ni-Y system have been attracting great interest as effective strengthening components because of their unique structural characteristics and deformation ***,the phase relationships in LPSOs are complicated and unclear,which restricts the design of advanced magnesium-based *** aim of the present work is to experimentally determine the phase equilibria relationships focusing on LPSOs and establish the thermodynamic description for Mg-Ni-Y *** types of LPSOs,that is,14H,12R,18R and 10H,are confirmed through equilibrated alloys and high-resolution transmission electron microscopy(HR-TEM).The formation enthalpies of LPSOs(14H,12R,18R and 10H) are calculated based on density functional theories(DFT) calculations.A new ternary compound,termed as τ phase,is observed for the first time which is likely to be the distorted structure of 12R as determined from the TEM image which shows a 12-layer closed packing plane distance of 3.252nm and a shear angle of 83.2°between(0002) and(10■0) *** on the determined phase equilibria relationship,the Mg-Ni-Y system is assessed and a selfconsistent description is obtained where the LPSOs are modeled as the stoichiometric *** comparison between the calculation result and experimental data suggests the accuracy of the present thermodynamic database in the Mg-rich corner.