Author:Chaona Liu ^abc1, Li Tian ^c1, Yueming Li ^d, Fuyuan Zheng ^c, Yunhui Li ^b, Qingming Xu ^b, Jianwei Zhu ^b, Wenfei Li ^ab, Guorui Zhao ^c

Jurnal:Composites Part A: Applied Science and Manufacturing

DOI:https://doi.org/10.1016/j.compositesa.2025.109527

Abstract / 摘要

This work overcomes the long-standing brittleness and poor machinability of B₄C by in-situ introduced conductive ScB₂C₂ network via reactive hot-pressing. The optimized composite containing 20 vol% ScB₂C₂ (BS-20) achieves a record fracture toughness of ∼ 10.5 MPa·m^1/2—over twice that of monolithic B₄C—enabled by residual stress fields from thermal-expansion mismatch and atomically coherent interfaces that promote crack deflection and bridging. Simultaneously, the percolating ScB₂C₂ network enables a semiconductor-to-conductor transition (∼ 0.65 × 10³ S/m), thereby unlocking electro-discharge machining of complex geometries, a critical advance for practical deployment. Furthermore, the BS-20 composite demonstrated exceptional laser ablation resistance, sustaining high power densities (up to ∼ 1.6 × 10⁷ W/cm²) without catastrophic failure, due to enhanced mechanical properties, energy dissipation and protective oxide scale formation. This work introduces a new class of damage-tolerant, electro-machinable, and laser-resistant B₄C-based composites, establishing a generalizable strategy for designing multifunctional ceramics capable of reliable performance in extreme environments spanning aerospace, defense, and precision engineering.

Keyword / 关键词

Boron carbide; In situ reaction; Thermopressed sintering; Rare-earth ternary layered ceramics