CALPHAD Modeling and Microstructure Investigation of Mg–Gd–Y–Zn Alloys

Janet Meier, Josh Caris, Alan A. Luo

Research output: Chapter in Book/Report/Conference proceedingConference contributionpeer-review

1 Scopus citations

Abstract

In this study, CALPHAD (CALculation of PHAse Diagrams) modeling was used to design and optimize Mg–Gd–Y–Zn alloys containing long period stacking order (LPSO) phases. The selected compositions were evaluated using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction to identify major phases and determine their area fractions. It was seen in as-cast samples that a blocky LPSO 14H phase formed at the grain boundaries while a filament-type LPSO 14H formed in the Mg grains. As the rare earth (RE) and Zn concentrations increased, eutectic Zn-rich intermetallics and more of the RE-rich blocky LPSO formed along grain boundaries. After annealing, an increase in the Zn-rich intermetallic area fraction, decrease in bulky LPSO area fraction, and increase in filament-type LPSO were observed. In higher alloyed samples, a Zn- and Y-rich phase was observed that was not consistent with the predicted or reported phase. These results indicate the present CALPHAD databases well represent the LPSO 14H formation in the Mg–Gd–Y–Zn system studied and can be used to tailor the microstructure to potentially improve the strength and ductility in these alloys. Further investigation is needed to determine if the existing reliably databases model the other secondary phases.

Original languageEnglish
Title of host publicationMagnesium Technology 2020
EditorsJ. Brian Jordon, Victoria Miller, Vineet V. Joshi, Neale R. Neelameggham
PublisherSpringer
Pages61-69
Number of pages9
ISBN (Print)9783030366469
DOIs
StatePublished - 2020
Externally publishedYes
EventMagnesium Technology Symposium held at the 149th Annual Meeting and Exhibition, TMS 2020 - San Diego, United States
Duration: Feb 23 2020Feb 27 2020

Publication series

NameMinerals, Metals and Materials Series
ISSN (Print)2367-1181
ISSN (Electronic)2367-1696

Conference

ConferenceMagnesium Technology Symposium held at the 149th Annual Meeting and Exhibition, TMS 2020
Country/TerritoryUnited States
CitySan Diego
Period02/23/2002/27/20

Funding

Acknowledgements This work was funded by the Army Research Laboratory (ARL) and Terves LLC. The authors would like to acknowledge Dr. Vincent Hammond with ARL, Dr. William Meier of Oak Ridge National Laboratory, and the Light Metals and Manufacturing Laboratory members at The Ohio State University for their insightful discussions. This material is based upon the work supported by the Army Contracting Command—Adelphi, MD under Contract No W911QX-18-P-0038. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of ARL. This work was funded by the Army Research Laboratory (ARL) and Terves LLC. The authors would like to acknowledge Dr. Vincent Hammond with ARL, Dr. William Meier of Oak Ridge National Laboratory, and the Light Metals and Manufacturing Laboratory members at The Ohio State University for their insightful discussions. This material is based upon the work supported by the Army Contracting Command—Adelphi, MD under Contract No W911QX-18-P-0038. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of ARL.

FundersFunder number
Light Metals and Manufacturing Laboratory
Terves LLCW911QX-18-P-0038
Oak Ridge National Laboratory
Army Research Laboratory

    Keywords

    • Alloy development
    • CALPHAD
    • Long period stacking order (LPSO)
    • Magnesium alloys
    • Microstructure

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