The relation between ductility at high temperature and solid solution in Mg alloys

作     者：D.F.Shi C.M.Cepeda-Jiménez M.T.Pérez-Prado 

作者机构：IM DEA Materials InstituteC/Eric Ka ridel228906 GetafeMadridSpain Department of Materials SciencePolytechnic University of Madrid/Universidad Politecnica de MadridE.T.S.de Ingenieros de Caminos28040MadridSpain Department of Physical MetallurgyCENIMCSICAv.Gregorio del Amo 828040 MadridSpain 

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

年 卷 期：2022年第10卷第1期

页      面：241-256页

核心收录：

学科分类：0806[工学-冶金工程] 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：funding from the Madrid region under programme S2018/NMT4381-MAT4.0-CM project Funding from projects PID2019111285RB-I00 and PID2020-118626RB-I00 awarded by the Spanish Ministry of Science, Innovation and Universities financial support from the China Scholarship Council (Grant no 201706050154) 

主　　题：Magnesium Solute segregation Slip trace analysis Ductility Deformation mechanisms 

摘      要：This work investigates the effect of solid solution on ductility and on the activation of individual deformation mechanisms at moderate temperatures and at quasi-static strain rates in Mg-Zn and Mg-Al alloys. With that aim, four solid solution Mg-Zn and Mg-Al binary alloy ingots containing 1 and 2 wt.% solute atoms were subjected to hot rolling and subsequent annealing to generate polycrystals with similar average grain size and basal-type texture for each composition. The activity of the different slip systems after tensile testing at 150°C and at 250°C was evaluated in pure Mg and in the alloys by EBSD-assisted slip trace analysis. In addition, segregation of Zn and Al atoms at grain boundaries during the thermo-mechanical processing was characterized by HAADF-STEM and EDX. It was found that while the addition of Al and Zn atoms to pure Mg does not lead to major changes in the mechanical strength at the investigated temperatures, it does enhance ductility significantly, especially at 250℃. Our results show that this increase in ductility cannot be attributed to a higher activation of non-basal systems in the alloys, as reported earlier, as the incidence of non-basal systems is indeed considerably higher in pure Mg. This work suggests, on the contrary, that the ductility increase may be attributed to the presence of a more homogenous basal activity in the alloys due to a lower degree of orientation clustering, to grain boundary solute segregation, and to a higher slip diffusivity at grain interiors.