Trends in transition metal solute diffusion in metals: The case of tungsten

Abstract

The solute diffusion regulates many properties and phenomena of metal alloys. Decades of research has led to lots of knowledge of interrelationships between diffusion parameters and transition metal (TM) solutes properties in metals. But none has provided a universal relationship to elucidate the underlying physics of TM solute diffusion in metals. In this paper, we systematically study TM solutes diffusion in tungsten using the first-principles calculations coupled with harmonic transition state theory. We found the solute migration energies vary parabolically across the TM series reaching a maximum at V, Mo, and W for 3d, 4d, and 5d, respectively. The correlation factor is temperature-dependent in an Arrhenius-like way, whose fitted correlation energies and pre-factors are inversely proportional to the solute migration energies. Using the database of TM solute diffusion in tungsten developed here and other existing databases, we identify the role of the matrix metals on the law of solute diffusion. When the atomic radii of matrix metals are larger than TM solutes, the solute diffusion is dominated by metallic bonds between the solute and matrix atoms, whose solute migration energy follows a positive correlation to the melting point of the solute element. While for the reverse case, the solute diffusion is controlled by solute-induced lattice distortions and their solute migration energy shows a negative correlation with the solute radius.