Variation of long-period stacking order structures in rapidly solidified Mg97Zn1Y2 alloy

Matsuda, Mitsuhiro; Kawamura, Yoshihito; Ikuhara, Yuichi; Nishida, Minoru

doi:10.1016/j.msea.2004.10.040

Cited by 325 publications

(174 citation statements)

References 8 publications

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“…The Mg 12 ZnY phase with 18R-type long period ordered (LPO) structure was known as the 1 phase in ternary Mg-Zn-Y phase diagrams, and several periods such as 18R-, 10H-, 14H-, and 24R-type were found in the Mg-Zn-Y alloys. [3][4][5][6][7] The Mg 12 ZnY phase is believed to suppress the growth of Mg grains at high temperatures, and is known to have a strong oxidation effect.…”

Section: Introductionmentioning

confidence: 99%

Microstructures and Mechanical Properties of Mg96Zn2Y2 Alloy Prepared by Extrusion of Machined Chips

et al. 2009

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Hot extrusion of machined chips of Mg 96 Zn 2 Y 2 (at%) alloy was carried out at 623 K, and microstructures and mechanical properties of the extruded Mg 96 Zn 2 Y 2 alloy were investigated. The alloy consisted of -Mg, Mg 12 ZnY, and Mg 3 Zn 3 Y 2 phases, and the Mg grains had a mean grain size of 450 nm. The Mg 12 ZnY phase was frequently observed inside the fine Mg grains. In addition, oxidation occurred around cavities remaining after extrusion. The extruded alloy exhibited a high 0.2% proof strength of 495 MPa and elongation of 3% at room temperature. The Mg grain refinement and dispersion of Mg 12 ZnY and Mg 3 Zn 3 Y 2 phases caused by hot extrusion led to high strength at room temperature. Further, the extruded alloy also exhibited superplasticity at temperatures of 623 and 723 K with initial strain rates from 2 Â 10 À1 S À1 to 2 Â 10 À3 S À1 . The maximum elongation was 450% at 723 K with an initial strain rate of 2 Â 10 À3 S À1 . Grain boundary sliding of Mg grains is the dominant deformation mechanism for the alloy at high temperature ranges.

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Section: Introductionmentioning

confidence: 99%

Microstructures and Mechanical Properties of Mg96Zn2Y2 Alloy Prepared by Extrusion of Machined Chips

et al. 2009

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“…The interval of the periodic fringes is 1.6 nm, which corresponds to that of 18R-type LPSO (1.56 nm). 5,8) However, an irregular fringe (arrowed position) is also observed. The interval of the irregular fringe is 2.1 nm, which corresponds to 24R-type LPSO (2.08 nm).…”

Section: Methodsmentioning

confidence: 95%

Structural and Compositional Modulation in Transformation of LPSO Structure in Mg97Zn1Y2 Cast Alloys

et al. 2013

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This study investigated modulation of the long period stacking order (LPSO) structure in aged Mg 97 Zn 1 Y 2 alloys using conventional transmission electron microscopy (TEM) and aberration-corrected high-angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). The irregular stacking sequence of a fragment of 24R-type LPSO acts as a catalyst for the transformation from 18R-to 14H-type LPSO. The elementary step of the transformation from 18R-to 24R-type takes place by the ledge-pair movement on different (0001) Mg planes with Shockley partial dislocations. Each ledge has a transition region in front of it. The transition regions are HCP-type stacking sequence with lower Zn and Y concentrations than those of the FCC-type enrichment layer. The solute elements migrate easily in the region, where solute elements produce a kind of diffusion field. Therefore, structural modulation occurs by a mechanism resembling diffusionaldisplacive transformation. Local strain analysis using HAADF-STEM images has elucidated that lattice spacing of (0001) Mg in the FCC-type enrichment layer is shorter than that in the HCP-type transition region. These structural and compositional irregularities are an elementary step in the transformation of LPSO in Mg 97 Zn 1 Y 2 alloys. A diffusionaldisplacive type transformation mechanism in LPSO has been proposed.

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“…[7][8][9] In the present paper, the Mg 12 ZnY phase signifies 18R-type LPO structure, while other types of LPO structures formed in the Mg-Zn-Y alloys are simply described as ''LPO structure'', and when the structure is confirmed as a phase, it is described as an ''LPO phase''.…”

Section: Introductionmentioning

confidence: 89%

Microstructure and Mechanical Properties of Mg-Zn-Y Rolled Sheet with a Mg12ZnY Phase

et al. 2010

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Ternary Mg-Zn-Y alloy sheets with several volume fractions of a Mg 12 ZnY phase were prepared by hot-rolling at 623 K. Volume fraction of the Mg 12 ZnY phase was increased with increasing of Zn and Y contents in the Mg 100ÀxÀy Zn x Y y (x ¼ 1$6, y ¼ 2$9 at%) alloys, and achieved more than 85% in an Mg 85 Zn 6 Y 9 alloy. (002) pole figures showed both of basal planes of the Mg 12 ZnY and Mg phases have a tendency to incline toward parallel to the sheet surface. However, it was considered that the formation of a basal plane texture in the Mg 12 ZnY phase is difficult compared with that in the Mg phase, due to a kink deformation. An Mg 90:5 Zn 3:25 Y 6:25 alloy sheet exhibited a 0.2% proof strength, an ultimate tensile strength, and an elongation of 353 MPa, 400 MPa, and 5%, respectively, at room temperature, and 279 MPa, 375 MPa, and 12%, respectively, at 523 K. Although elongation was slightly less than those in the commercial Mg sheets, the Mg 90:5 Zn 3:25 Y 6:25 alloy sheet showed high strength over a wide temperature range compared to those in commercial Mg alloys.

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Variation of long-period stacking order structures in rapidly solidified Mg97Zn1Y2 alloy

Cited by 325 publications

References 8 publications

Microstructures and Mechanical Properties of Mg<SUB>96</SUB>Zn<SUB>2</SUB>Y<SUB>2</SUB> Alloy Prepared by Extrusion of Machined Chips

Microstructures and Mechanical Properties of Mg<SUB>96</SUB>Zn<SUB>2</SUB>Y<SUB>2</SUB> Alloy Prepared by Extrusion of Machined Chips

Structural and Compositional Modulation in Transformation of LPSO Structure in Mg<sub>97</sub>Zn<sub>1</sub>Y<sub>2</sub> Cast Alloys

Microstructure and Mechanical Properties of Mg-Zn-Y Rolled Sheet with a Mg<SUB>12</SUB>ZnY Phase

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