Solutes that reduce yield strength anisotropies in magnesium from first principles

Michael R. Fellinger, Louis G. Hector, Dallas R. Trinkle

Research output: Contribution to journalArticlepeer-review

Abstract

Using Labusch-type solid solution strengthening models parameterized with DFT-computed solute-dislocation interaction energies, we perform a computational search for 63 solutes across the periodic table to find those that lower anisotropy ratios (non-basal to basal CRSS) of magnesium potentially increasing its ductility per the von Mises criterion. For this purpose, we compute changes in strength for solutes as a function of composition and temperature, and compute anisotropy ratios for solutes that include both rare earth and non-rare earth elements. We specifically focus on solute-dislocation interaction energies in the following DFT-optimized dislocations as representative of three non-basal plastic deformation modes: 〈c+a〉 edge, (101¯2) tension twinning edge, and the (101¯1) compression twinning edge. We find that solute-induced changes in non-basal deformation modes can be approximated using a second-order polynomial in the size misfit of the solutes, which permits rapid screening of solutes. Our approach to identify solutes known to improve strengthening incorporates solute solubility, and suggests other solutes that not have been previously explored for strengthening. The 8 rare-earth solutes that our method suggests as the best, ordered by increasing anisotropy ratios at their optimal concentrations, are: Gd, Tb, Dy, Nd, Ho, Er, Tm, and Yb. The 12 non-rare-earth solutes that our method suggests as the best, ordered by increasing anisotropy ratios, are: Y, Mn, Sc, Pb, Ca, Ag, Bi, Tl, Zn, Li, Ga, and Al. Of these, Gd, Nd, Er, Yb, Y, Mn, Ca, Zn, Li, and Al are used in commercial Mg alloys.

Original languageEnglish (US)
Article number013607
JournalPhysical Review Materials
Volume6
Issue number1
DOIs
StatePublished - Jan 2022
Externally publishedYes

ASJC Scopus subject areas

  • General Materials Science
  • Physics and Astronomy (miscellaneous)

Fingerprint

Dive into the research topics of 'Solutes that reduce yield strength anisotropies in magnesium from first principles'. Together they form a unique fingerprint.

Cite this