Rapid synthesis and properties characterization of MoAlB prepared by high pressure and high temperature method

MAB phases, renowned for exceptional creep resistance, thermal shock resistance, and damage tolerance, are emerging as promising structural ceramics. However, conventional synthesis methods face limitations including prolonged processing, complex by-product formation, and high energy consumption, hindering widespread adoption. To address these challenges, we developed an efficient high pressure and high temperature (HPHT) approach for synthesizing high-purity MoAlB with excellent crystallinity. Scanning electron microscopy reveals a disordered-orientation lamellar microstructure comprising individual layers tens of nanometers thick. MoAlB sample exhibited a Vickers hardness of 17.6 GPa, with outstanding mechanical properties, including high fracture toughness and Young’s modulus of 8.09 MPa·m 1/2 and 316.2 GPa, respectively. Transmission electron microscopy confirms HPHT-induced stacking faults, edge dislocations, and vacancies that collectively enhance mechanical performance. Microstructural analysis of Vickers indentation zones demonstrates active toughening mechanisms including transgranular fracture deflections, crack branching, and bridging. XPS analysis verifies anisotropic bonding in MoAlB, where electron transfer between Al layers and Mo-B layers critically stabilizes the crystal structure. Crucially, comparative synthesis analysis demonstrates that HPHT processed MoAlB achieves superior mechanical properties with significantly reduced processing time than traditional method. These findings establish HPHT synthesis as a promising route for advanced MAB phase material fabrication.