Intermetallic phase formation in Mg–Ag–Nd (QE) and Mg–Ag–Nd–Zn (QEZ) alloys

Rainer Schmid-Fetzer, Jian Feng Nie, Xiaojun Zhao, Houwen Chen

Research output: Chapter in Book/Report/Conference proceedingConference PaperOther

Abstract

The intermetallic phase (designated δ phase) in the solution-treated microstructure of commercial magnesium alloy QE22 (Mg–2.5Ag–2.0Nd–0.7Zr, wt%) has been investigated using scanning electron microscopy, electron diffraction, atomic-resolution scanning transmission electron microscopy (STEM), and thermodynamic modeling. In contrast to the previous reports, an orthorhombic structure (space group Cmcm) and a composition of NdAgMg11 are determined. The present experimental data are used to construct a thermodynamic description of the Mg–Ag–Nd system which is embedded in a multicomponent Mg alloy database. Implications on the formation of temperature range and thermal stability of this phase and alloy solidification are discussed based on the calculated Mg–Nd–Ag phase diagram and Scheil solidification paths of alloys. The impact of Ag-replacement in such QE alloys by Zn-addition in the Mg–Ag–Nd–Zn (QEZ) alloy system is elaborated using appropriate thermodynamic simulations to reveal the competition with other intermetallics. These data are suggested to contribute to ICME of magnesium alloys.

Original languageEnglish
Title of host publicationMagnesium Technology 2020
EditorsJ. Brian Jordon, Victoria Miller, Vineet V. Joshi, Neale R. Neelameggham
PublisherSpringer-Praxis
Pages71-78
Number of pages8
ISBN (Print)9783030366469
DOIs
Publication statusPublished - 3 Apr 2020
EventMagnesium Technology Symposium 2020 - San Diego, United States of America
Duration: 23 Feb 202027 Feb 2020
https://www.tms.org/TMS2020

Publication series

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

Conference

ConferenceMagnesium Technology Symposium 2020
Abbreviated titleTMS 2020
CountryUnited States of America
CitySan Diego
Period23/02/2027/02/20
Internet address

Keywords

  • Crystal structure
  • ICME
  • Secondary phases
  • Thermodynamics

Cite this

Schmid-Fetzer, R., Nie, J. F., Zhao, X., & Chen, H. (2020). Intermetallic phase formation in Mg–Ag–Nd (QE) and Mg–Ag–Nd–Zn (QEZ) alloys. In J. B. Jordon, V. Miller, V. V. Joshi, & N. R. Neelameggham (Eds.), Magnesium Technology 2020 (pp. 71-78). (Minerals, Metals and Materials Series). Springer-Praxis. https://doi.org/10.1007/978-3-030-36647-6_13