Reinforcing metal matrix composites (MMCs) with nanophases of distinct characteristics is an effective strategy for utilizing their individual advantages and achieving superior properties of the composite. In this study, a combination of molecular level mixing (MLM), segment ball milling (SBM), and in-situ solid-phase reaction was employed to fabricate Cu matrix composites (TiC-CNT/Cu) reinforced with TiC decorated CNT (TiC@CNT) and in-situ nanoscale TiC particles. The HRTEM results revealed the epitaxial growth of interfacial TiC on the surface of CNT (i.e., CNT(0002)//TiC(200), and the formation of a semi-coherent interface between TiC and Cu matrix, which can effectively enhance the interfacial bonding strength and optimize load transfer efficiency of CNT. The independent in-situ TiC nanoparticles got into the grain interior through grain boundary migration, thereby significantly enhancing both strain hardening capacity and strength of the composite by fully utilizing the Orowan strengthening mechanism. Moreover, the enhanced bonding strength of the interface can also effectively suppress crack initiation and propagation, thereby improving the fracture toughness of the composite. The TiC-CNT/Cu composite with 1.2 vol.% CNT exhibited a tensile strength of 372 MPa, achieving a super high strengthening efficiency of 270, while simultaneously maintaining a remarkable ductility of 21.2%. Furthermore, the impact toughness of the TiC-CNT/Cu composite exhibited a significant enhancement of 70.7% compared to that of the CNT/Cu composite, reaching an impressive value of 251 kJ/m², thereby demonstrating exceptional fracture toughness. Fully exploiting the synergistic strengthening effect of different nanophases can be an effective way to improve the comprehensive properties of MMCs.

中文翻译：

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在 CNT 双纳米相和晶内原位 TiC 增强的 Cu 基复合材料中实现强度-延展性平衡


增强具有不同特性的纳米相的金属基复合材料 （MMC） 是利用其各自优势并获得复合材料卓越性能的有效策略。本研究采用分子水平混合 （MLM）、分段球磨 （SBM） 和原位固相反应相结合的方式，制备了用 TiC 装饰的 CNT （TiC@CNT） 和原位纳米级 TiC 颗粒增强的铜基复合材料 （TiC-CNT/Cu）。HRTEM 结果揭示了 CNT 表面界面 TiC 的外延生长（即 CNT（0002）//TiC（200），并在 TiC 和 Cu 基体之间形成半相干界面，可以有效增强界面结合强度并优化 CNT 的载荷传递效率。独立的原位 TiC 纳米颗粒通过晶界迁移进入晶界内部，从而充分利用 Orowan 强化机制，显著提高了复合材料的应变硬化能力和强度。此外，界面的增强粘结强度还可以有效抑制裂纹的萌生和扩展，从而提高复合材料的断裂韧性。碳纳米管含量为 1.2 vol.% 的 TiC-CNT/Cu 复合材料表现出 372 MPa 的拉伸强度，实现了 270 的超高强化效率，同时保持了 21.2% 的显著延展性。此外，TiC-CNT/Cu 复合材料的冲击韧性与 CNT/Cu 复合材料相比显著提高了 70.7%，达到了令人印象深刻的 251 kJ/m²，从而表现出优异的断裂韧性。 充分利用不同纳米相的协同强化作用是改善 MMCs 综合性能的有效途径。