Phase stability and mechanical property trends for MAB phases by high-throughput ab initio calculations

• Published in: Materials & design Vol. 241; p. 112959
• Main Authors: Koutná, Nikola, Hultman, Lars, Mayrhofer, Paul H., Sangiovanni, Davide G.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.05.2024; Elsevier
• Subjects: Ab initio; Ductility; Elastic constants; MAB phase; Phase stability; Ab initio; Elastic constants; MAB phase; Phase stability; Ductility
• DOI: 10.1016/j.matdes.2024.112959
• ISSN: 0264-1275; 1873-4197

MAB phases (MABs) are atomically-thin laminates of ceramic/metallic-like layers, having made a breakthrough in the development of 2D materials. Though offering a vast chemical and phase space, relatively few MABs have been synthesised. To guide experiments, we perform high-throughput ab initio screening of MABs that combine group 4–7 transition metals (M); Al, Si, Ga, Ge, or In (A); and boron (B) focusing on their phase stability trends and mechanical properties. Considering the 1:1:1, 2:1:1, 2:1:2, 3:1:2, 3:1:3, and 3:1:4 M:A:B ratios and 10 phase prototypes, synthesisability of a single-phase compound for each elemental combination is estimated through formation energy spectra of competing dynamically stable MABs. Based on the volumetric proximity of energetically-close phases, we identify systems in which volume-changing deformations may facilitate transformation toughening. Subsequently, chemistry- and phase-structure-related trends in the elastic stiffness and ductility are predicted using elastic-constants-based descriptors. The analysis of directional Cauchy pressures and Young's moduli allows comparing mechanical response parallel and normal to M–B/A layers. The suggested promising MABs include Nb3AlB4, Cr2SiB2, Mn2SiB2 or the already synthesised MoAlB. •MAB phases of the group 4–7 transition metals (M); Al, Si, Ga, Ge, or In (A); and boron (B) are screened.•Experimentally known phase prototypes are considered together with those designed using common diboride structures.•Re2AlB2, W2SiB2, and Mn2SiB2 are suggested to activate transformation toughening upon loading.•Trends in the elastic stiffness and ductility are predicted using elastic-constants-based descriptors.•The most promising MABs include Nb3AlB4, Cr2SiB2, Mn2SiB2 or the known MoAlB.