Effect of Cd on matrix structure ordering and aging precipitation evolution in a Mg-Gd-Cd solid-solution alloy  

作　　者：Lin-Lin Liu Wei Sun Cuixiu Liu Pengyang Sun 

机构地区：[1]Institute of Microstructure and Property of Advanced Materials,Beijing University of Technology,Beijing 100124,China

出　　处：《Journal of Magnesium and Alloys》2023年第8期2833-2852,共20页镁合金学报（英文）

基　　金：The authors would like to acknowledge the financial supports from the National Natural Science Foundation of China[grant number 11274027];Beijing Municipal Natural Science Foundation[grant number 2092005].

摘　　要：The formation and evolution of Gd-rich precipitates companying with the matrix structure ordering in a Mg_(97)Gd_(2)Cd_(1)(at.%)solid-solution alloy aged at 200℃have been systemically investigated using high-angle annular dark-field scanning transmission electron microscopy(HAADF-STEM).The results show that Gd-rich precipitation dynamics during the aging treatment are noticeably affected by a continuous ordering transformation in the matrix.The ordering transformation process involving mainly re-distribution of Cd atoms was revealed to occur in the following way:random super-saturated solid solution(S.S.S.S.)→B19-type ordered domains→D019-type ordered domains.Four Gd(Cd)-rich precipitates,G.P.Ⅰ zone,G.P.Ⅱ zone,β′andβ_(1)phases,have been observed to be formed in sequence to coexist with the various ordered domains.Based on the HAADF-STEM characterization on the aging microstructures at different aging stages,it can be concluded that the Cd-addition and related matrix structure ordering can play significant roles in modifying the early-stage G.P.zone structure,altering the morphology ofβ′precipitates and promoting the forming ability of theβ_(1)precipitate.

关 键 词：Mg-Gd-Cd alloy Ordering transformation Aging microstructure Precipitation evolution HAADF-STEM 

分 类 号：TG146.22[一般工业技术—材料科学与工程]