Achieving synergistic strength and toughness in Al/SiC composites: A controlled comparison of bioinspired laminated versus uniform architectures

The performance comparison between uniformly dispersed and bioinspired architectures in metal matrix composites has long been limited by the absence of rigorously controlled experimental validation. To address this gap, this study employed a carbon fiber-assisted gelcasting method to fabricate crack-free, low-volume-fraction (31.2 vol.%) uniform SiC preforms. They were compared against laminated SiC preforms (∼30 vol.%) prepared via freeze casting, with both architectures densified by aluminum infiltration under identical conditions. The results demonstrate that the laminated structure achieves a remarkable strength–toughness synergy, with its flexural strength and fracture toughness enhanced by 7.3% and 18.2%, respectively, compared with the uniform structure. This improvement is attributed to a transition in the toughening mechanism from an intrinsic to an extrinsic mechanism dominated by crack bridging, highlighting that spatial configuration constitutes a critical performance-regulating dimension beyond traditional compositional design, and offering a new paradigm for the development of high-performance composites. • Crack-free uniform preforms were created using a novel sacrificial fiber method • Uniform vs. laminated MMCs were compared at matched reinforcement content • Synergistic strength and toughness enhancement was revealed in laminated MMCs • Superior performance is linked to extrinsic toughening via crack bridging