| 1 | Rotational and translational domains of beta precipitate in aged binary Mg-Ce alloys显示文摘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. | B.Z.Sun H.X.Zhang Y.Dong J.X.Ren Y.Tian G.M.Xie J.Tan Y.H.Sun Na Xiao | 2021 | Journal of Magnesium and Alloys2021，9，3： | 2 |
| 2 | An insight into a novel Mg2InSm prismatic plate in Mg-In-Sm alloy显示文摘Prismatic precipitate platelet is always purposefully designed in the microstructure of magnesium alloys due to its greater contribution to yield stress.In this study,with an introduction of In into Mg-Sm system,a category of novel{1010}_(α) prismatic platelets has replaced thoroughly the traditionalβ’precipitate formed in magnesium rare earth(Mg-RE)alloys.Herein,the microstructural characteristics of platelet are investigated particularly by atomic scale scanning transmission electron microscopy.It is confirmed that the platelet has a Mg_(2) InSm composition and can maintain a coherent relationship with α-Mg matrix.Importantly,on account of the similarities between In and Mg atoms,the Mg_(2) InSm prismatic platelet could be structurally categorized as a generalizedβ'precipitate with a(Mg_(2) In)Sm-type DO_(19) structure when both In and Mg are regarded as an equivalent atom.Thus,the addition of In into Mg-Sm alloy induces the formation ofβ'precipitate.Furthermore,the formedβ'prismatic platelets generally have a large average aspect ratio.The findings are of great significance to construct the effective precipitation strengthening phases and optimize the microstructure of Mg-based alloys. | J.Wang X.L.Lu Y.Tian Q.Y.Huang H.B.Xie B.Z.Sun L.R.Liu | 2022 | Journal of Materials Science & Technology2022，，30： | 0 |
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