Rotational and translational domains of beta precipitate in aged binary Mg-Ce alloys  

作　　者：B.Z.Sun H.X.Zhang Y.Dong J.X.Ren Y.Tian G.M.Xie J.Tan Y.H.Sun Na Xiao 

机构地区：[1]School of Materials Science and Engineering,Northeastern University,Shenyang 110819,China [2]State Key Lab Rolling&Automat,Northeastern University,Shenyang 110819,China [3]Key Laboratory for Anisotropy and Texture of Materials,Ministry of Education,Northeastern University,Shenyang 110819,China [4]Analytical and Testing Center,Northeastern University,Shenyang 110819,China

出　　处：《Journal of Magnesium and Alloys》2021年第3期1039-1056,共18页镁合金学报（英文）

摘　　要：The structural evolution fromβ_(1)(Mg_(3)Ce)toβ(Mg_(12)Ce)precipitates,which takes place at the over-aged stage of binary Mg-Ce alloys,are investigated by high-angle annular dark-field scanning transmission electron microscopy.The structural transformation mainly occurs in the{111}_(β1)crystallographic planes,where the newly formedβlattices exhibit two categories of domain structures,namely rotational and translational domains.The rotational domain is composed of threeβdomains(β_(RA),β_(RB)andβ_(RC)),which are related by a 120°rotation with respect to each other around the 111_(β1)axis of theirβ_(1)parent phase.The{111}_(β1)crystallographic planes can provide four sets of sublattices with the same orientation for an initial nucleation ofβlattice.It leads to the formation of four translationalβdomains(β_(TA),β_(TB),β_(TC)andβ_(TD)),among which any two differ by a vector of 1/6112_(β1).We deduce theoretically that there exist twenty-fourβdomains during this transition.However,considering the interfacial misfit,only one-third of domains can grow up and eventually formsβribbon.Furthermore,a majority ofβribbons overlap partiallyβ_(1)plate,which is beneficial to relax interfacial strain amongβ,β_(1)andα-Mg matrix(α/β/β_(1)).The configuration of multipleβdomains can effectively regulate interfacial misfit ofα/βandβ/β_(1),which are responsible for enhancing the hardness and strength of Mg-Ce alloy.Additionally,this study aims to provide some clues to improve the over-aged performance of magnesium alloys by constructingβdomains and optimizing theα/β/β_(1)interface.

关 键 词：Magnesium alloys HAADF-STEM Rotational domain Translational domain Phase transition Interfacial misfit 

分 类 号：TG146.22[一般工业技术—材料科学与工程]