金属材料的强化通常以牺牲塑性来提高强度，本项申请提出利用短程有序增加位错运动的临界切应力以及促进变形孪晶形成的特性，来提高FCC高熵合金的屈服强度和塑性。研究热处理对CoCrFeMnNi和AlxCoCrFeNi两种FCC高熵合金体系短程有序的影响，考察合金组元对短程有序和层错能的影响。采用TEM等技术，分析高熵合金的短程有序、层错能与位错交滑移、平面滑移和孪生等变形机制选择的相关性。采用OM、ECCI、EBSD、XRD及TEM等技术，研究变形FCC高熵合金位错组态、柏氏矢量、位错密度、位错与孪晶的交互作用、孪晶类型、孪晶片层厚度和体积分数等，明确短程有序对不同层错能FCC高熵合金变形组织演变的影响。结合不同温度的拉伸结果，明确短程有序对不同层错能FCC高熵合金力学性能的影响规律。通过本项研究，不仅可为制备高强度、高塑性高熵合金奠定理论，还能突破传统FCC金属仅用层错能调控变形机制的局限。

Usually, when the strength of metals increases, the plasticity decreases. In the present project, the short range ordering is used to increase the strength and plasticity of FCC high entropy alloys, since the short range ordering can improve the critical shear stress of dislocation movement and is in favor of the formation of deformation twins. In order to control and change the short range ordering and stacking fault energy of the CrMnFeCoNi and AlxCoCrFeNi alloy systems, the effect of heat treatment and alloys component on the short range ordering and stacking fault energy will be analyzed. Then, the relationship between short range ordering, stacking fault energy and the choice of deformation mechanisms including cross slipping, planar slipping and twining will be studied by using of TEM. The results can break through the limit that only stacking fault energy was considered during analyzing the deformation behavior of traditional FCC metals. In order to reveal the effect of short range ordering on the microstructure evolution of FCC high entropy alloys with different stacking fault energies during deformation process, the dislocation configuration, Burgers vector of dislocations, dislocation density, type of twin boundaries, lamellar thickness and fraction of twins, and interaction of dislocations and twin boundaries will be characterized by using of OM, ECCI, EBSD, XRD and TEM. Meanwhile, according to the results of tensile test under different temperatures, the effect of short range ordering on mechanical properties of FCC high entropy alloys with different stacking fault energies will be analyzed. The results can lay the theoretical foundation for preparing high entropy alloys with high strength and plasticity.