Microstructure and Mechanical Properties of Mg-2.5%Tb-0.78%Sm Alloy After Ecap and Ageing

Archives of Metallurgy and Materials

L.L. Rokhlin¹  L. Litynska-Dobrzynska²  J. Dutkiewicz²  K. Bryła³  K. Mroczka³  P. Kurtyka³ 

[1] Baikov Institute of Metallurgy and Material Science, Russian Academy of Sciences, 49, Leninsky Prospect, 119991 Gsp-1, Moscow, Russia;Institute of Metallurgy and Material Science, Polish Academy of Sciences, 25 w. Reymonta str., 30-059 Kraków, Poland;Institute of Technology, Pedagogical University of Cracow, 2 podchorazych str., 30-084 Kraków, Poland

关键词: Keywords : magnesium alloys with rare earth metals;    ECAP;    microstructure;    ageing;    mechanical properties;   

DOI  :  10.2478/amm-2013-0022

学科分类：金属与冶金

来源: Akademia Gorniczo-Hutnicza im. Stanislawa Staszica / University of Mining and Metallurgy

【 摘 要 】

The influence of ageing and Equal Channel Angular Pressing (ECAP) on the microstructure and mechanical properties of Mg-2.5%Tb-0.78%Sm alloy has been examined. The microhardness changes during ageing at 200ºC show a slight increase. The aged microstructure at maximum hardness contains Mg12(Tb,Sm) - metastable β’ phase of size about 2-10 nm as dispersed precipitates. The orientation relationship between β’ phase and the matrix was found as follows:(0001)Mg || (1¯10)β′, [21¯10]Mg || [116]β′. The ECAP passes were performed by two procedures: “I” - four passes at 350ºC; “II” - one pass at 370ºC, second pass at 340ºC and third pass at 310ºC. The grain size was reduced about 200 times as a results of ECAP process according “I” and “II” procedure. The grain refinement by ECAP improves significantly the compression yield strength and hardness. The Hall-Petch relationship was confirmed basing on microhardness measurements and the grain size after ECAP. The Mg24(Tb,Sm)5 and Mg41(Sm,Tb)5 particles smaller than 150 nm are located mainly at grain and subgrain boundaries and they prevent grain growth during ECAP processing. The microstructure evolution during ECAP can be described as dynamic recovery and continuous and discontinuous dynamic recrystallization.

【 授权许可】

Unknown