ABSTRACT Biological composites, such as nacre, achieve exceptional mechanical performance through hierarchical architectures that balance strength and toughness‐characteristics rarely replicated in synthetic materials. In this study, we present a biomimetic strategy for fabricating B 4 C/CNT composite films using sequential boric acid precipitation on carbon nanotube (CNT) films, followed by spark plasma sintering (SPS)‐driven in situ B 4 C formation. This approach combines the lightweight and high energy‐absorption properties of CNTs with the structural robustness of B 4 C, resulting in a synergistic composite. This material mimics the “brick‐and‐mud” structure of pearl layers, with alternating “brick” layers rich in B 4 C and “mud” layers rich in CNTs. The maximum density of B 4 C/CNT composite films is 1.78 g/cm 3 , with a dynamic compressive strength of 1098 MPa. The energy absorption capacity, as measured in laser‐induced projectile impact testing (LIPIT), is 3.5% higher than that of CNT films. Crack propagation is prevented through layer delamination, CNT bridging, and B 4 C grain deflection. During the air erosion process at 1000°C, B 4 C selectively oxidizes to form a dense B 2 O 3 glass phase, which acts as an in‐situ protective barrier, thereby exhibiting excellent anti‐erosion performance. This work provides a solution to intrinsic strength‐toughness‐density trade‐off in structural materials, with significant implications for aerospace and protective engineering.
Xu et al. (2026) studied this question.