Ultralight High-Entropy Nanowire Scaffolds for Extreme-Temperature Functionality.

Area of Science:

• Materials Science
• Nanotechnology
• Metallurgy

Background:

• High-entropy alloys (HEAs) offer tunable properties but suffer from high density.
• Lightweight materials are crucial for advanced applications, yet traditional metals are often too dense.

Purpose of the Study:

• To engineer lightweight functional materials by combining high-entropy alloys with structural porosity.
• To achieve metal-like properties at ultralow densities using entropy-architected metamaterials.

Main Methods:

• Electrodeposition of FeCoNiCrCu HEA nanowires into porous templates.
• Freeze-casting to create 3D "bird's nest" scaffolds with densities <1% of bulk metal.
• Structural, magnetic, and thermal property characterization.

Main Results:

• Achieved ultralow density metamaterials (<1% of bulk metal density).
• Retained disordered face-centered-cubic phase with Curie temperatures >1000 K.
• Demonstrated thermal diffusivity comparable to titanium alloys (≈0.211 mm² s⁻¹).
• Identified nanoscale Cu segregation enhancing magnetic ordering and thermal stability.

Conclusions:

• Entropy-architected nanowire metamaterials offer a pathway to ultralightweight functional materials.
• Co-engineering configurational entropy and architectural hierarchy enables high-temperature performance.
• These materials are suitable for extreme-environment applications requiring low density and high functionality.