本项目针对航空发动机涡轮结构中DD5单晶与FGH98粉末高温合金连接的需求，以高熵合金热力学特征及优异的力学性能为启发，提出设计高熵合金中间层调控DD5单晶与FGH98粉末高温合金扩散焊界面微观组织结构，以实现DD5单晶与FGH98粉末高温合金高强韧扩散焊。本项目首先通过高熵合金中间层的成分设计与微结构调控，获得适用于本项目连接体系的高熵合金中间层，并阐明中间层设计原理。进而开展添加中间层的DD5单晶与FGH98粉末高温合金扩散焊实验研究，分析扩散焊界面反应热力学原理及动力学过程。最后，通过对接头性能及失效模式的研究揭示高熵合金中间层对扩散焊接头的强韧化机制。本项目研究将建立高熵合金中间层材料及扩散焊工艺设计方法，为提高DD5/FGH98接头强度与韧性提供技术与理论支撑。

In order to achieve the joining of DD5 single crystal and FGH98 powder metallurgy superalloy in aero-engine turbine structure, high entropy alloy interlayer was designed to diffusion bond DD5 and FGH98 based on the thermodynamic characteristics and excellent mechanical properties of high entropy alloy. The high entropy alloy interlayer could control the microstructure of the diffusion bonding joint, improving the joint strength and toughness. The project first focused on designing the composition and microstructure of high entropy alloy interlayer. The high entropy alloy suitable to the DD5/FGH98 system was obtained, and the design principle of interlayer was revealed. Then the diffusion bonding of DD5 and FGH98 using high entropy alloy interlayer was performed. The thermodynamic and dynamics of the interfacial reaction was analyzed. Finally, the strengthening and toughening mechanism of the joint was revealed through investigating the property and fracture of the joint. The research results of this project would build the design principle of the high entropy alloy interlayer and diffusion bonding process, providing technical and theoretical support for the improvement of the DD5/FGH98 joint strength and toughness.