Abstract An efficient powder metallurgy route including wet dispersion, high energy ball milling (HEBM) and spark plasma sintering (SPS) was proposed to fabricate carbon nanotube reinforced molybdenum‑hafnium‑carbon (CNT-reinforced MHC) composites. To improve the dispersion efficiency of carbon nanotubes (CNTs) in the molybdenum (Mo) matrix, acid treatment was used to de-agglomerate CNTs. Carbon nanotube/hafnium hydride (CNT/HfH2) powder prepared by wet dispersion and the powder subsequently milled with Mo through HEBM to fabricate MHC composite powder. The results show that this powder metallurgy process improved the dispersion uniformly of HfC and grain size. The strengthening mechanism of dispersion strengthening, grain refinement, lattice distortion and purification of free oxygen improved the relative density, microstructures and mechanical properties of the CNT-reinforced MHC composites. As a result, compared to other control groups and Mo based composites, the 30 h ball milling time of CNT-reinforced MHC composite (30 h composite) exhibits simultaneous enhancement in relative density, mechanical properties and improvement in microstructure. This work provides a feasible way to fabricate high-performance Mo matrix composites.

中文翻译：

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一种制备碳纳米管增强钼铪碳复合材料的粉末冶金路线

摘要 提出了一种包括湿法分散、高能球磨 (HEBM) 和放电等离子烧结 (SPS) 的有效粉末冶金路线来制备碳纳米管增强钼铪碳 (CNT 增强 MHC) 复合材料。为了提高碳纳米管 (CNT) 在钼 (Mo) 基体中的分散效率，使用酸处理来解聚 CNT。通过湿法分散制备的碳纳米管/氢化铪（CNT/HfH2）粉末，随后通过HEBM与Mo一起研磨以制造MHC复合粉末。结果表明，该粉末冶金工艺改善了 HfC 的均匀分散和晶粒尺寸。弥散强化、晶粒细化、晶格畸变和游离氧净化等强化机制提高了相对密度，CNT增强MHC复合材料的微观结构和力学性能。因此，与其他对照组和 Mo 基复合材料相比，CNT 增强 MHC 复合材料（30 小时复合材料）的 30 小时球磨时间同时表现出相对密度、机械性能和微观结构的改善。这项工作为制造高性能钼基复合材料提供了一种可行的方法。