Abstract
Diffusion bonding with innovative interlayers is critical for manufacturing high-precision aerospace turbine components requiring exceptional comprehensive performances, yet achieving simultaneous strength and ductility in superalloy bonding joints remains challenging. Developing high-performance interlayer material, introducing effective strengthening strategies, and elucidating deformation mechanisms in the superalloy joints can address this issue. This study introduces a multi-interlayer composite bonding technique using a “BNi2/high entropy alloy/BNi2” sandwich structured interlayer to join powder metallurgy superalloy FGH98. The liquid BNi2 interlayer eliminated interfacial defects, reducing the risk of a brittle fracture at the interface. The high entropy alloy interlayer of FeCoNiTiAl promoted atomic diffusion between the interlayer and base metals, facilitating the in situ formation of TiB2 borides, M3B2 borides, γ' nanoparticles and comprising distinct zones with different deformation capabilities. This heterogeneous joint microstructure resulted in an extraordinary strength-ductility synergy through strain partitioning and load transfer. Among these zones, the strengthening effect in the Ti-boride zone (TBZ) with in situ TiB2 borides was crucial, particularly at elevated temperatures. High work-hardening and deformation capabilities were attributed to TiB2’s effectiveness in obstructing dislocation movement and generating stacking faults within the borides. As a result, an ultrahigh ultimate tensile strength of 1410 ± 10 MPa, a total elongation at fracture of 19 ± 0.5 % at room temperature, and a maximum tensile strength of 981 ± 20 MPa at 800 °C were achieved in the bonding joint.
Original language | English |
---|---|
Article number | 121186 |
Journal | Acta Materialia |
Volume | 295 |
DOIs | |
State | Published - 15 Aug 2025 |
Keywords
- Deformation mechanisms
- FGH98 superalloy
- High entropy alloy
- In situ TiB
- Joint microstructure
- Multi-interlayer composite bonding