Evolution of long-period stacking order (LPSO) in Mg97Zn1Gd2 cast alloys viewed by HAADF-STEM multi-scale electron tomography

Sato, Kazuhisa; Tashiro, Shunya; Matsunaga, Shuhei; Yamaguchi, Y.; Kiguchi, Takanori; Konno, Toyohiko J.

doi:10.1080/14786435.2018.1468940

Cited by 7 publications

(4 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Long-period stacking order precipitates that can exist at the grain boundaries, as well as intragranularly, are classified into two types, one that forms during solidification, and the other upon annealing (Kawamura and Yamasaki, 2007;Li et al, 2018;Sato et al, 2018). It should be noted that, alloy composition permitting, the entire grains are composed of lamella of LPSO together with bands of α-Mg, while LPSO precipitates along the grain boundaries can also be present.…”

Section: Systems Containing Lpso Phasesmentioning

confidence: 99%

A Review on Developments in Magnesium Alloys

Kaya

2020

Front. Mater.

View full text Add to dashboard Cite

In order to facilitate the understanding of the current research efforts and directions, this article first introduces the anomalous/problematic features of magnesium (Mg) and presents the recent approach of stacking fault energy (SFE)-based alloying element selection to lessen or eliminate this problem. Stacking fault energy computations via ab initio techniques necessitate an understanding of the free electron density distribution around atoms in a solid solution. Therefore, the assessment of the role of atoms by also considering the possibility of short range order (SRO) formation rather than a random solid solution has been revisited. Two possible types of SRO have been indicated. The relevant electronic interactions between the host Mg and the alloying element atoms are more clearly incorporated in a generally less known model by Miedema based on atomic-level thermodynamics rather than in Hume-Rothery rules. This more successful approach has also been addressed here. An evaluation founded on these premises, introducing the relatively more recent Mg alloy systems, has been given in terms of their achievements toward healing the problematic features of Mg alloys. The spectrum of alloy systems discussed ranges from doping of Mg to dilute alloy systems and to some rich alloy systems that offer remarkable properties. Among the first category, an unorthodox addition, doping with oxygen, and its implications, has been presented. The dilute alloy systems and their compositional design based on SRO and SFE together with their potentials have been reviewed. Among the rich alloy compositions, the most interesting precipitate systems, that is, the ones involving order and intermetallic formations, long-period stacking order phases, and quasi-crystals, have been discussed. Among all the alloying elements, one that deserves particular attention, calcium, with its implications such as being economical, offering environmentally friendly Mg metallurgy, and remedial effects on the shortcomings of engineering properties, and a closely related issue of calcium oxide (CaO) addition have been scrutinized. This article also makes an attempt to point out the future directions throughout the text, whenever possible.

show abstract

Section: Systems Containing Lpso Phasesmentioning

confidence: 99%

A Review on Developments in Magnesium Alloys

Kaya

2020

Front. Mater.

View full text Add to dashboard Cite

show abstract

“…. )-Zn alloys, referred to as Type II, the LPSO-phase does not appear in the as-cast condition and a subsequent high-temperature thermal treatment is required to develop it [11][12][13][14][15][16][17][18]. After a solution treatment, a hardness peak can be reached by ageing the material at low temperatures.…”

Section: Introductionmentioning

confidence: 99%

Study of Tensile and Compressive Behavior of ECO-Mg97Gd2Zn1 Alloys Containing Long-Period Stacking Ordered Phase with Lamellar Structure

Garcés,

Medina,

Pérez

et al. 2024

Metals

View full text Add to dashboard Cite

A suitable heat treatment in the Mg97Gd2Zn1 (at.%) alloy in the as-cast condition results, after extrusion at high temperature, in a two-phase lamellar microstructure consisting of magnesium grains with thin lamellar shape precipitates and long fibers of the 14H-Long-Period Stacking Ordered (LPSO) phase elongated in the extrusion direction. The magnesium matrix is not fully recrystallized and highly oriented coarse non-dynamically recrystallized (non-DRXed) grains (17% volume fraction) elongated along the extrusion direction remain in the material. The deformation mechanisms of the extruded alloy have been studied measuring the evolution of the internal strains during in situ tension and compression tests using synchrotron diffraction radiation. The data demonstrate that the macroscopic yield stress is governed by the activation of the basal slip system in the randomly oriented equiaxed dynamic recrystallized (DRXed) grains. Non-DRXed grains, due to their strong texture, are favored oriented for the activation of tensile twinning. However, the presence of lamellar-shape precipitates strongly delays the propagation of lenticular thin twins through these highly oriented grains and they have no effect on the onset of the plastic deformation. Therefore, the tension–compression asymmetry is low since the plasticity mechanism is independent of the stress mode.

show abstract

“…However, the details of the local interfacial structure, including the solute segregation of the CLM, are still unclear. The latest electron-microscopy techniques enable the local characterization of structural and chemical irregularities [14,15]. The purpose of this study is to clarify the microstructure and solute segregation of orientation-controlled 316L SS, produced by controlling the scanning strategy of LPBF (hereafter, LPBF 316L SS) by transmission electron microscopy (TEM) and energy-dispersive x-ray spectroscopy (EDS).…”

Section: Introductionmentioning

confidence: 99%

Microstructure and Solute Segregation around the Melt-Pool Boundary of Orientation-Controlled 316L Austenitic Stainless Steel Produced by Laser Powder Bed Fusion

et al. 2022

Self Cite

View full text Add to dashboard Cite

For this article, we studied the microstructure and solute segregation seen around the melt pool boundary of orientation-controlled 316L austenitic stainless steel produced by laser powder bed fusion, using transmission electron microscopy and energy-dispersive x-ray spectroscopy. We found that the solidification cellular microstructures could be visualized with the aid of solute segregation (Cr and Mo) during solidification. Mn–Si–O inclusions (10–15 nm in diameter) were distributed along the lamellar boundaries, as well as in the dislocation cell walls. It is believed that the grain growth of the inclusions can be effectively suppressed by rapid quenching during the laser powder-bed fusion process. A thin region without cellular microstructures was observed at the melt-pool boundary. The cellular spacing widened near the bottom of the melt-pool boundary, owing to the decrease in the cooling rate. Atomic-structure analysis at the lamellar boundary by high-resolution transmission electron microscopy revealed a local interfacial structure, which is complementary to the results of electron back-scatter diffraction.

show abstract

Evolution of long-period stacking order (LPSO) in Mg₉₇Zn₁Gd₂ cast alloys viewed by HAADF-STEM multi-scale electron tomography

Cited by 7 publications

References 22 publications

A Review on Developments in Magnesium Alloys

A Review on Developments in Magnesium Alloys

Study of Tensile and Compressive Behavior of ECO-Mg97Gd2Zn1 Alloys Containing Long-Period Stacking Ordered Phase with Lamellar Structure

Microstructure and Solute Segregation around the Melt-Pool Boundary of Orientation-Controlled 316L Austenitic Stainless Steel Produced by Laser Powder Bed Fusion

Contact Info

Product

Resources

About