TiC含量对Mo基复合材料显微组织和力学性能的影响

Effect of TiC Content on Microstructure and Mechanical Properties of Mo-based Composites

摘要:

本研究旨在探究碳化钛（TiC）含量对钼（Mo）基复合材料显微组织及力学性能的影响，为航空发动机领域开发高性能耐热钼材提供科学依据。通过放电等离子烧结（spark plasma sintering，SPS）技术，制备了TiC质量分数分别为10%、20%和30%的TiC/Mo复合材料。研究发现，TiC/Mo复合材料的强化机制主要归因于晶内颗粒强化和晶界强化。TiC在高温下会与Mo基体之间存在扩散效应，在二者界面之间存在一定宽度的过渡区，通过XRD分析可知过渡区为(Ti, Mo)C。TiC和Mo两相晶格结合紧密，这在原子尺度范围内进一步证明两相实现了牢固结合。通过拉伸与硬度试验，发现添加10%和20% TiC的TiC/Mo复合材料展现出优异的力学性能。TiC/Mo复合材料的断裂行为主要受晶间微裂纹扩展的控制，而微裂纹的扩展取决于晶间和晶内发展的竞争。本研究深入揭示了晶间和晶粒内部TiC颗粒的耦合作用对TiC/Mo复合材料力学性能的影响。

Abstract:

The influence of titanium carbide (TiC) content on the microstructure and mechanical properties of molybdenum (Mo)-based composites was investigated, aiming to provide a scientific basis for the development of high-performance and heat-resistant molybdenum materials for aerospace engines. TiC/Mo composites containing 10wt%, 20wt%, and 30wt% TiC were prepared using spark plasma sintering (SPS) technique. The results indicate that the strengthening mechanisms of TiC/Mo composites are primarily attributed to intragranular particle strengthening and grain boundary strengthening. At elevated temperatures, TiC diffuses into the Mo matrix, forming a transition zone of measurable width at the interface of the two phases. XRD analysis confirms that this transition zone comprises (Ti, Mo)C. The crystal lattices of the TiC and Mo phases exhibit strong bonding, which is further corroborated by atomic-scale observations. Tensile and hardness tests reveal that TiC/Mo composites with 10wt% and 20wt% TiC demonstrate superior mechanical properties. The fracture behavior of these composites is primarily governed by the propagation of intergranular microcracks, which is influenced by the competition between intergranular and intragranular crack development. This study provides critical insights into the coupling effects of intergranular and intragranular TiC particles on the mechanical performance of TiC/Mo composites.