多主元高熵合金具有一些传统合金无法比拟的性能，BCC结构高熵合金较差的室温塑性制约了其应用，基于钢铁中碳元素可扩大奥氏体区的特性，提出利用间隙元素碳促使BCC结构高熵合金向FCC结构转变改善其塑性并提高力学性能，减少高熵合金中昂贵的FCC结构稳定化元素Co、Ni等使用的新思路。选用典型的高熵合金系，依据价电子浓度判据通过强BCC结构化元素Al含量变化设计特定BCC结构的新合金，获得间隙元素碳对高熵合金BCC结构相调控规律和调控能力的量化表征并给出调控的理论判据。通过电子探针、三维原子探针等高精测定仪对高熵合金中碳的固溶、碳化物析出和分布等特性进行表征，阐释碳的存在形态及影响因素，结合性能测试数据揭示碳的存在形态与性能的关联机制。项目在BCC结构高熵合金的塑性改善方法上具有明显理论创新，在探索经济型高性能高熵合金设计方面具有重要的实际价值，在促进和扩大高熵合金应用方面具有显著社会意义。

High entropy alloys (HEAs), which contain multi-principal elements, have many excellent properties those traditional materials can’t achieve. High brittleness and low ductility of the body-centered cubic (BCC) type of HEAs restrict its application in the future. To improve the ductility of BCC HEAs, this work will use interstitial C to promote the phase transition of HEAs from BCC to face-centered cubic (FCC) solid solution phase, based on the stabilizing effect of interstitial C on the FCC phase in steels. It will reduce use of expensive FCC stabilizing elements such as Co and Ni and increase the performance of HEAs at the same time. To quantitatively analyse the effect of interstitial C on phase transition from BCC to FCC solid solution phase in HEAs and obtain its’ theoretical criterion, the most widely studied HEA families are chosen as the studied alloy system, and some specific BCC HEAs are designed by changing content of the strong BCC stabilizing element Al according to the valence electron concentration (VEC) criterion. A Field Emission Electron-probe Microanalyzer and 3 Dimensional Atom Probe will be used to accurately examine the solid solubility of carbon, the composition and distribution of precipitated carbides. Moreover, the existing state of interstitial C in HEAs and its effect factors will be systemically investigated, and a relationship between its existing states and the mechanical properties will be given. This work is trying to explore a novel method to improve the ductility of BCC HEAs at a low cost, and develop a high performance HEA. It will accelerate the application of HEAs.