Diffusion bonding (DB) with interlayers is sought-after for manufacturing high-performance turbine disks of powder metallurgy (PM) superalloys with precise and intricate inner cavity structures. Developing novel interlayer materials is challenging but crucial for enhancing bonding quality and joint properties. We designed a multi-interlayer composite bonding (MICB) method, employing sandwich-structured interlayers of “BNi2/high entropy alloy (HEA)/BNi2”, to join a PM superalloy FGH98. The MICB joint exhibited an ultrahigh shear strength of ∼1132 MPa and exceptional ductility, indicating a typical ductile fracture pattern with numerous dimples. Owing to the introduction of liquid BNi2 interlayer, initial bonding interfaces were eliminated and replaced by newborn grain boundaries (GBs), preventing brittle interfacial fracture. Due to the diffusion of Al/Ti/Ta from the base metals (BMs), massive ordered γ' nanoparticles also precipitated in the joint. Moreover, the addition of HEA foil reduced the stacking fault energy (SFE) of the joint and facilitated the formation of deformation twins (DTs). Thus, during the deformation process, the γ' nanoparticles, and multiple substructures like stacking faults (SFs), Lomer-Cottrell (L-C) locks, DTs, and 9R phases enhanced the work-hardening capability and strengthened the joint. Simultaneously, the multiplication and interaction of DTs induced a softening mechanism of dynamic recrystallization (DRX) during the entire deformation process and dominated when the plastic instability occurred, resulting in numerous adiabatic shear bands (ASBs) consisting of γ/γ' nano-bands, which indicates a significant improvement of the joint ductility.

中文翻译：

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超强和延展性高温合金接头与高熵合金改性的新型复合夹层结合


带有夹层的扩散键合 （DB） 是制造具有精确和复杂内腔结构的粉末冶金 （PM） 高温合金的高性能涡轮盘的热门技术。开发新型夹层材料具有挑战性，但对于提高粘合质量和接合性能至关重要。我们设计了一种多层复合键合 （MICB） 方法，采用“BNi2/高熵合金 （HEA）/BNi2”的夹层结构夹层，以连接 PM 高温合金 FGH98。MICB 接头表现出 ∼1132 MPa 的超高剪切强度和出色的延展性，表明具有大量凹痕的典型韧性断裂模式。由于液体 BNi2 中间层的引入，初始键合界面被消除，取而代之的是新生晶界 （GB），防止了脆性界面断裂。由于 Al/Ti/Ta 从贱金属 （BMs） 中扩散，块状有序 γ' 纳米颗粒也在接头中沉淀。此外，HEA 箔的添加降低了节理的堆叠断层能 （SFE） 并促进了变形孪生 （DT） 的形成。因此，在变形过程中，γ' 纳米颗粒和多个子结构，如堆叠断层 （SFs）、Lomer-Cottrell （L-C） 锁、DTs 和 9R 相增强了加工硬化能力并加强了接头。同时，DTs 的增殖和相互作用在整个变形过程中诱导了动态再结晶 （DRX） 的软化机制，并在塑性失稳发生时占主导地位，导致许多由 γ/γ' 纳米带组成的绝热剪切带 （ASB），这表明接头延展性得到显着改善。