Atomic diffusion in liquid nickel: First-principles modeling

Area of Science:

• Materials Science
• Computational Chemistry
• Physical Chemistry

Background:

• Diffusion coefficients in liquid nickel are critical for materials development.
• Experimental data for impurity diffusion in liquid nickel is scarce.

Purpose of the Study:

• To calculate self- and impurity diffusion coefficients in liquid nickel systems.
• To investigate the temperature and concentration dependence of diffusion.
• To provide data relevant for nickel-based superalloys and cemented carbides.

Main Methods:

• Utilizing the ab initio molecular dynamics approach.
• Performing simulations at temperatures ranging from 1903 to 2303 K.
• Analyzing temperature-dependent diffusion coefficients and concentration-dependent impurity diffusion.

Main Results:

• Calculated self- and impurity diffusion coefficients for various Ni-X systems (X=C, Co, N, Nb, Ta, Ti, W).
• Determined activation energies and frequency factors for temperature-dependent diffusion.
• Investigated concentration-dependent impurity diffusion in the Ni-Co system.
• Achieved excellent agreement with limited existing experimental data.

Conclusions:

• The study provides essential theoretical data for liquid nickel diffusion.
• The findings support the development of advanced nickel-based superalloys and cemented carbides.
• Ab initio molecular dynamics is a reliable method for assessing diffusion in liquid metals.