Achieving thermally stable nanoparticles in chemically complex alloys via controllable sluggish lattice diffusion

Area of Science:

• Materials Science
• Metallurgy
• Solid-state Physics

Background:

• Nanoparticle strengthening is key for high-performance structural materials.
• Poor thermal stability and particle coarsening limit nanoparticle effectiveness at high temperatures.

Purpose of the Study:

• To develop ultra-stable nanoparticles in a complex alloy for high-temperature structural applications.
• To understand the mechanism behind nanoparticle stabilization at elevated temperatures.

Main Methods:

• Fabrication of a Ni-Co-Fe-Cr-Al-Ti-B chemically complex alloy.
• Diffusion kinetic simulations to analyze elemental interdiffusion.
• First-principles calculations to investigate atomic interactions and stability.

Main Results:

• Achieved ultra-stable nanoparticles at 800–1000°C.
• Demonstrated that Cobalt (Co) addition significantly reduces interdiffusion coefficients, especially for Aluminum (Al).
• Identified Al incompressibility, induced by Co, as critical for controlling sluggish lattice diffusion (SLD).

Conclusions:

• The study presents a novel strategy for creating thermally stable nanoparticles in structural alloys.
• Controlling sluggish lattice diffusion via elemental additions like Co is effective for enhancing high-temperature material stability.
• Findings advance the design of advanced structural materials with superior property-microstructure stability.