A formation criterion for Order-Disorder (OD) phases of the Long-Period Stacking Order (LPSO)-type in Mg-Al-RE (Rare Earth) Ternary Systems

Kishida, Kyosuke; Yokobayashi, Hideyuki; Inui, Haruyuki

doi:10.1038/s41598-017-12506-0

Cited by 29 publications

(11 citation statements)

References 42 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The observed composition Mg 75.4 Al 9.0 Y 15.6 appears to be close to the former, supporting the present interstitial analysis. It is also worthwhile to note that the present interstitial occupation turns out to be higher than that in the previous report 0.56, 34) which may be caused by differences of the alloy compositions.…”

Section: Resultscontrasting

confidence: 63%

The LPSO Structure with an Extra Order beyond Stacking Periodicity

2020

View full text Add to dashboard Cite

We have investigated a novel long-period stacking/order (LPSO) structure in a Mg 75 Al 10 Y 15 alloy, based on electron diffraction, scanning transmission electron microscopy (STEM) observations and first-principles calculations. Fundamental lattice of the present LPSO structure is identified as one of the stacking polytypes of 10H-type, and the in-plane 6©ð1 210Þ hcp superlattice order is well developed as represented by the L1 2-type Al 6 Y 8 cluster arrangement. We find that, across the stacking direction, the inter-cluster order tends to be further developed beyond its periodicity, showing an extra order which doubles the 10H-stacking periodicity. We have constructed the LPSO variant models including such extra inter-cluster order, and their formation energy comparison has confirmed that the extra order becomes indeed stable when the L1 2-Al 6 Y 8 cluster contains interstitial atoms. The interstitial effects turn out to be prominent in favor of Y atom, as being consistent with the STEM observations.

show abstract

Section: Resultscontrasting

confidence: 63%

The LPSO Structure with an Extra Order beyond Stacking Periodicity

2020

View full text Add to dashboard Cite

show abstract

“…Long-period stacking order phases are further complicated by in-plane ordering in 14H and 18R types (Kishida et al, 2015;Kim et al, 2018b). This complication manifests itself with the presence of L1 2 type clusters, and the order is violated in one dimension, leading to the definition of order-disordered crystallographic structure in some Mg-TM-RE alloys (Yokobayashi et al, 2011a;Okamoto et al, 2014;Iwatake et al, 2015;Kishida et al, 2015Kishida et al, , 2017. The in-plane order may be a long-range type as in Mg-Al-Gd system Tane et al, 2015;Kim et al, 2018b) or may be composition dependent as in Mg-Y-Zn system, being present more locally in relatively dilute alloys, and long-range type in richer Mg-Y-Zn alloys (Egusa and Abe, 2012).…”

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

“…STEM image and corresponding atomic model shown in Figure illustrates the L1 2 type ordered RE 8 Zn 6 cluster embedded in FCC building block. Recent report on LPSO structure by Kishida et al focused on the in‐plane order in Mg–Y–Zn alloy system. L12 type ordered RE 8 Zn 6 clusters have a “Φ” shape based on characterization.…”

Section: Precipitate Structurementioning

confidence: 99%

Atomic Scale Investigation on Precipitates and Defects of Mg–RE Alloys: A Review

Zhu

Chen

2018

Adv Eng Mater

View full text Add to dashboard Cite

Magnesium rare-earth (Mg-RE) alloys with are playing an increasingly important role in many industrial fields due to the improvement of mechanical properties and formability from RE alloying. In addition to the traditional researches on the relationship between macroscopic mechanical properties and micro-structures, atomic scale characterization methods have been rapidly developed and widely applied to reveal the interior of these alloys. Precipitates and defects are known to be the dominant factors that influence the mechanical behaviors as well as plastic responses. Common strengthening precipitates in Mg-RE alloys include long perio d stacking ordered structure (LPSO), β serial, γ serial metastable precipitates. This review mainly considers and discusses the recent development in atomic scale investigation on Mg-RE alloy, including the common strengthening phases and interactions between defects (dislocations, twins) and existing strengthening precipitates.

show abstract

A formation criterion for Order-Disorder (OD) phases of the Long-Period Stacking Order (LPSO)-type in Mg-Al-RE (Rare Earth) Ternary Systems

Cited by 29 publications

References 42 publications

The LPSO Structure with an Extra Order beyond Stacking Periodicity

The LPSO Structure with an Extra Order beyond Stacking Periodicity

A Review on Developments in Magnesium Alloys

Atomic Scale Investigation on Precipitates and Defects of Mg–RE Alloys: A Review

Contact Info

Product

Resources

About