Carbon nanotubes (CNTs) were synthesized in situ by chemical vapor deposition of methane over nano-ZrB₂ matrix using Ni/Y catalysts. Well-grown CNTs with tangled and long bodies and mainly composed of well-crystallized graphite were obtained when the Ni content reaches 10 wt%. The CNT/ZrB₂ nanocomposites obtained by spark plasma sintering at 1400°C exhibited full density and optimal mechanical properties. The flexural strength and fracture toughness of the nanocomposites were 1184 ± 52 MPa and 10.8 ± 0.3 MPa·m^1/2, respectively. Results indicated that the dispersion of CNTs in situ can improve composite performance, rendering the mechanical properties of the CNT/ZrB₂ nanocomposites synthesized in situ considerably superior to those of monolithic ZrB₂ nanoceramics and CNT/ZrB₂ nanocomposites synthesized using the traditional method. The toughening mechanisms included crack deflection, crack bridging, CNT debonding, pull-out, and fracture.

中文翻译：

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原位增强CNT / Ni / Y / ZrB2纳米复合材料的制备与性能

通过使用Ni / Y催化剂在甲烷在纳米ZrB ₂基质上化学气相沉积甲烷来原位合成碳纳米管（CNT）。当Ni含量达到10wt％时，获得了具有缠结且长的主体且主要由结晶良好的石墨组成的生长良好的CNT。通过火花等离子体烧结在1400°C下获得的CNT / ZrB ₂纳米复合材料表现出全密度和最佳的机械性能。纳米复合材料的抗弯强度和断裂韧性分别为1184±52 MPa和10.8±0.3 MPa·m ^1/2。结果表明，碳纳米管的原位分散可以改善复合材料的性能，从而使碳纳米管/ ZrB ₂的力学性能得到改善。原位合成的纳米复合材料明显优于使用传统方法合成的整体式ZrB ₂纳米陶瓷和CNT / ZrB ₂纳米复合材料。增韧机制包括裂纹挠曲，裂纹桥接，CNT脱胶，拉出和断裂。