Atomic hysteretic diffusion enables high-strength TiAl/Ni joints via cluster-plus-glue-atom modeled GCFMs.

Area of Science:

• Materials Science
• Metallurgy
• Composite Materials

Background:

• High-performance Ni/TiAl composite structures require improved strength-ductility synergy.
• Joining dissimilar metals like Ni and TiAl presents significant challenges in maintaining mechanical integrity.

Purpose of the Study:

• To develop an innovative gradient-driven atomic hysteretic diffusion strategy for Ni/TiAl composite structures.
• To achieve mechanical performance in brazed joints that matches the TiAl substrate.

Main Methods:

• Utilized cluster-plus-glue-atom modeled gradient composite filler metals (GCFMs) combining Ni-based and Zr-based alloys.
• Implemented spatiotemporal control of solid-liquid interfaces to induce atomic diffusion hysteresis.
• Engineered gradient-distributed Ni-based solid solutions and reinforced interfaces.

Main Results:

• Transformed brittle Ti-based intermetallic compounds into gradient Ni-based solid solutions.
• Achieved exceptional shear strength of 479 MPa in the K4169/TiAl brazed joint, comparable to the TiAl substrate.
• Demonstrated synergistic strengthening mechanisms including dispersion, solid solution, and covalent interfacial reinforcement.

Conclusions:

• The gradient-driven atomic hysteretic diffusion strategy offers a generalized framework for joining dissimilar metals.
• The developed GCFM approach enhances joint strength by 40% over conventional methods.
• This strategy enables the creation of damage-tolerant composite architectures crucial for aerospace applications.