Strong-Yet-Ductile Eutectic Alloys Employing Cocoon-Like Nanometer-Sized Dislocation Cells

Area of Science:

• Materials Science
• Metallurgy
• Nanotechnology

Background:

• Eutectic alloys (EAs) offer excellent castability for large structural parts.
• Conventional EAs (CEAs) lack competitive strength-ductility combinations.
• Nanoprecipitates are crucial for anchoring dislocations in advanced alloys.

Purpose of the Study:

• To develop a novel microstructural strategy for enhancing the mechanical properties of eutectic alloys.
• To investigate the effectiveness of a cocoon-like nano-meshed network of dislocations (CNN-D) in improving strength and ductility.
• To surpass the performance of existing CEAs and additively manufactured eutectic high-entropy alloys.

Main Methods:

• Thermomechanical processing of cast Ni-Fe-Al eutectic alloys.
• Recovery annealing to induce dislocation rearrangement.
• Microstructural analysis to characterize the cocoon-like nano-meshed network of dislocations (CNN-D).

Main Results:

• A unique cocoon-like nano-meshed network of dislocations (CNN-D), as fine as 26 nm, was successfully produced.
• The CNN-D facilitated nanometer-spaced planar slip bands, dynamically refining the microstructure.
• Enhanced strength and ductility were achieved, surpassing CEAs and additively manufactured alloys.

Conclusions:

• The CNN-D represents a novel microstructural strategy for performance enhancement in eutectic alloys.
• This approach is particularly effective for compositionally complex alloys utilizing nanoprecipitates.
• The study offers a new pathway for designing high-performance structural materials.