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...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 inter-layers 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 in-terfaces 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 orderedγ'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,theγ'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 ofγ/γ'nano-bands,which indicates a significant im-provement of the joint ductility.展开更多
基金support from the National Natural Science Foundation of China(Grant Nos.52075449,51975480,and 52222112)the Hong Kong Research Grant Council(RGC)(Grant No.21205621).
文摘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 inter-layers 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 in-terfaces 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 orderedγ'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,theγ'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 ofγ/γ'nano-bands,which indicates a significant im-provement of the joint ductility.
