Progress in stress-relieving methodologies of ceramic matrix composites/Ni-based superalloys joints: A review
Ceramic matrix composites (CMCs) offer exceptional high-temperature performance and lightweight characteristics, yet their limited manufacturability restricts fabrication of complex, large-scale structural components. Ni-based superalloys exhibit outstanding elevated-temperature properties, and hybrid CMC/superalloy components can significantly expand engineering applications. Interfacial residual stresses arising from thermal expansion coefficient (CTE) mismatch, thermal gradient differences, and phase transformations severely impair joint performance. This review systematically examines residual stress formation mechanisms in CMCs/Ni-based superalloys joints and summarizes mitigation methodologies including interlayer techniques, composite filler approaches, and interface structure design strategies. Key experimental findings from recent studies demonstrate that composite fillers incorporating nanoparticles (e.g., Ag-CuO-Al2O3, Si3N4, Sc2W3O12, graphene nanosheets, carbon nanotubes, WC) effectively regulate interfacial reactions and relieve residual stresses. For instance, Ag-Cu-Ti+Sc2(WO4)3 composite filler reduced residual stress in Cf/SiC-GH3536 joints, while graphene nanoplatelets reinforced AgCuTi fillers improved SiC/GH99 joint integrity. Mo and B inserts in SiCf/SiC-Ni-based superalloy joints provided microstructural control and reinforcement. These methodologies address the critical bottleneck of CTE mismatch-induced stress concentration, offering pathways to reliable CMC/superalloy hybrid structures for aerospace, energy, and propulsion applications. Challenges remain in scaling these techniques for industrial production and ensuring long-term stability under service conditions.