From Stability to Hardness: High-Throughput First-Principles Screening Reveals Promising MAB Phases for Advanced Engineering Applications

MAB phases are a class of layered ternary transition-metal borides, characterized by hard M-B slabs interleaved with softer A-element layers, and thus hold promise for wear-resistant and high-temperature structural applications. However, their compositional space and structural diversity remain insufficiently explored, limiting guidance for synthesis and property optimization. In this work, we perform a comprehensive exploration and screening of the MAB family using high-throughput first-principles calculations. We systematically identify 855 candidate MAB compounds with orthorhombic and hexagonal structures across multiple transition-metal families, which form the starting pool for subsequent stability and property evaluation. The workflow evaluates viability using three criteria: quantifying thermodynamic stability through formation energy and energy above the convex hull, confirming dynamical stability using phonon spectra, and evaluating mechanical stability via the Born criteria. We identify 336 MAB candidates that satisfy all three stability requirements, and further conduct a comprehensive evaluation and statistical analysis of their elastic constants and derived mechanical properties, including bulk, shear, and Young’s modulus as well as Vickers hardness, thereby elucidating how stoichiometry and composition influence hardness and brittle-ductile behavior. This study not only provides a curated set of experimentally viable MAB materials spanning diverse stoichiometries but also establishes a robust and transferable computational workflow for accelerating the discovery of layered ternary borides.