Dynamic mechanical response and failure behaviour of AlMgB₁₄-based ceramic: experimental observation, constitutive modelling and ballistic performance evaluation

AlMgB₁₄-based ceramics have emerged as promising materials for ballistic protection due to their ultra-hardness and low density. However, their dynamic mechanical behaviour and ballistic performance remain underexplored. In this work, the dynamic mechanical response and failure behaviour of an AlMgB₁₄-based material were systematically investigated through experiments, theoretical analysis and simulation. Quasi-static compression and split Hopkinson pressure bar testing revealed that compressive strength increased with strain rate, and the stress–strain response changed from linear elastic to non-linear plastic behaviour. Microfractography observations revealed that the ceramic failure mode transitioned from intergranular to transgranular with increasing strain rate. Plate impact tests were conducted to determine the Hugoniot elastic limit and spall strength of the AlMgB₁₄-based material. Additionally, experimental data and numerical simulations were used to determine the parameters of the Johnson–Holmquist II (JH-2) constitutive model. These parameters were validated by comparing simulated and experimental results for high-strain-rate deformation and fragmentation. Finally, ballistic simulations employing the established JH-2 model, including depth of penetration and high-velocity projectile impact of the AlMgB₁₄-based ceramic, showed good agreement with experimental results. Compared to conventional ceramic materials, the AlMgB₁₄-based ceramic demonstrated significantly higher ballistic resistance efficiency, effectively reducing projectile kinetic energy. This study elucidates the dynamic response and constitutive model of the AlMgB₁₄-based ceramic, offering valuable insights into its applications for designing bulletproof structures.