A unified description of ordering in HCP Mg-RE alloys. (1st February 2017)

• Record Type: Journal Article
• Authors: Natarajan, Anirudh Raju; Van der Ven, Anton
• Is Part Of: Acta materialia. Volume 124(2017)
• Page Start: 620
• Page End: 632
• Publication Date: 2017-02-01
• Subjects: Magnesium alloys -- Rare-earth -- Precipitation -- First-principles -- Thermodynamics; Materials -- Periodicals; Materials science -- Periodicals; Materials -- Mechanical properties -- Periodicals; Metallurgy -- Periodicals; Chemistry, Inorganic -- Periodicals; 620.112
• DOI: 10.1016/j.actamat.2016.10.057
• Languages: English
• ISSNs: 1359-6454

Abstract

Abstract: High throughput first-principles calculations were employed to unravel the thermodynamic stability of two sets of hierarchical phases, β P ‴ and β S ‴, in Mg-RE (rare-earth) alloys. The β P ‴ orderings (with compositions greater than x RE =0.125) are predicted to form in the Mg-{La, Ce, Pr, Nd, Pm, Sm} binary alloys, thus explaining experimental observations of RE atoms arranged as hexagonal rings in these alloys. Mg-{Sc, Y, Tb, Dy, Ho, Er, Tm, Lu} alloys are predicted to form β S ′ ( x RE =0.125) precipitates without hexagonal ring arrangements. The calculated misfit strains are used to infer the qualitative shapes of the precipitates and their relative aspect ratios. High aspect-ratio precipitates may be formed using alloying elements that encourage the formation of β P ‴ . The predictions in this study can be used to inform alloy design of precipitation strengthened magnesium alloys. Graphical abstract: Image 1