Atomic diffusion in liquid nickel : First-principles modeling

• Self- and impurity diffusion coefficients are assessed in the liquid nickel system by the fundamental ab initio molecular dynamics approach. The impurity diffusion coefficients in the Ni-X systems (X=C, Co, N, Nb, Ta, Ti, W) are mostly not available in the current literature. The simulations are performed at four temperatures, in the range from 1903 to 2303 K, which allows to extract activation energies and frequency factors for the temperature dependent diffusion coefficient assuming an Arrhenius-type behavior in the liquid. In addition to the temperature dependence, the concentration-dependent impurity diffusion was investigated for the Ni-Co system. The data are of relevance for the development of the state-of-the art Ni-based superalloys and alternative binder systems in cemented carbides. The obtained theoretical results are in very good agreement with the limited experimental data for the diffusion in liquid Ni systems.

Ämnesord

NATURVETENSKAP  -- Fysik -- Den kondenserade materiens fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Condensed Matter Physics (hsv//eng)

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