κʹ纳米相/FCC基体铸态高熵超合金的组织优化及性能调控

作为一种新型金属材料，高熵合金与传统合金的设计思路不同，并且拥有独特性能，因而成为金属材料领域的研究热点。前期工作发现，Al0.5FeCoNiC0.1合金凝固冷却后直接形成均匀的κʹ纳米相+FCC基体超合金组织，并且增加碳含量以及添加Ti，在超合金基体上形成高自润滑性石墨以及高硬度碳化物。在此基础上，本项申请拟开展二方面工作。首先，系统分析合金元素对凝固冷却形成κʹ相的耦合作用机理，结合第一性原理计算探讨κʹ相形成机制，调控κʹ相体积分数和颗粒尺寸，揭示合金室温/高温变形机制以及κʹ相体积分数和尺寸与合金室温/高温力学性能之间的关系。其次，调控高熵超合金碳化物以及石墨的形态、分布、尺寸和体积分数，揭示其组织特征与磨损性能之间的关系。通过本项研究，不仅能丰富超合金变形以及金属材料的磨损行为等相关理论，还可为高温合金以及耐磨材料的合金设计提供新思路。因此，具有重要的科学理论意义和工程实用价值。

High-entropy alloys (HEAs) consist of five or more principle elements, which is different from traditional alloys. Recently, this new alloys have widely attracted the attentions due to their unique compositions and excellent properties. In the previous investigation, it was found that the microstructure of as-cast Al0.5FeCoNiC0.1 HEA consists of FCC and nanoscale κʹ phases. In the present project, in order to control the size and volume fraction of κʹ phase, the effect of alloy composition on the formation of κʹ phase will be analyzed. According to the results of first- principle calculation, the formation mechanism of κʹ phase will be revealed. Then, the deformation behavior of HEAs containing κʹ phase will be studied, and the relationship between the size and volume fraction of κʹ phase and the mechanical properties at room temperature and high temperature will be analyzed. In addition, the morphology, distribution, size and volume fraction of carbide and graphite in HEAs containing κʹ phase will be tailored by the addition of alloying elements, and the relationship between the wear properties and the microstructure character of HEAs containing κʹ phase, carbide and graphite will be studied. The results of present project can not only enrich theories of the wear behavior and deformation mechanism, but also provide new methods to design high-temperature alloys and wear resistant materials. Therefore, the present project has important theoretical significance and engineering practical value.