Dynamic mechanical response of 7075Al hybrid composites reinforced with B₄C_p and SiC_p prepared via FHPS

Hybrid B₄C_p/SiC_p/7075 Al composites were fabricated via fast hot-press sintering. The mechanical behavior was evaluated under quasi-static and dynamic (1000-3000 s⁻¹) loading. A significant strain-rate-dependent failure transition was identified, shifting from ductile shear fracture to brittle fragmentation with increasing strain rate. The 50 wt% ceramic reinforced composite exhibited optimal performance, achieving a quasi-static strength of 914.8 MPa and a dynamic strength of 880.7 MPa at 2000 s⁻¹. Thermal softening caused a 3.7-12.4% strength reduction under dynamic loading compared to quasi-static values. Microstructural analysis confirmed that grain refinement, load transfer, and dislocation pinning are the primary strengthening mechanisms. These results provide critical insights for designing impact-resistant aluminum matrix composites in aerospace and defense sectors.