High-throughput ab-initio dilute solute diffusion database

Abstract

We demonstrate automated generation of diffusion databases from high-throughput density functional theory (DFT) calculations. A total of more than 230 dilute solute diffusion systems in Mg, Al, Cu, Ni, Pd, and Pt host lattices have been determined using multi-frequency diffusion models. We apply a correction method for solute diffusion in alloys using experimental and simulated values of host self-diffusivity. We find good agreement with experimental solute diffusion data, obtaining a weighted activation barrier RMS error of 0.176 eV when excluding magnetic solutes in non-magnetic alloys. The compiled database is the largest collection of consistently calculated ab-initio solute diffusion data in the world.

Exact Model of Vacancy-Mediated Solute Transport in Magnesium

“…Recently, Nandipati et al also found the distinction between 1b-1b and 1b-1b jump using self-learning kinetic Monte Carlo [64]. As previous computational studies [20][21][22][23] relied on the 8-frequency framework to model diffusion and identify which transition states to compute, these uncontrolled approximations can cause significant quantitative and qualitative errors in transport coefficients.…”

“…Transport coefficients are fundamental inputs for models at the length and time scales of microstructure evolution. However, computational modeling of transport coefficients for Mg alloys has used oversimplified models that lead to incorrect predictions, despite using accurate ab initio data as inputs [20][21][22][23].…”

“…3 contribute significantly to drag, but choosing a single value of ω 1b-1b = ω 1b-1b affects the two rings differently. Moreover, all prior DFT calculations [20][21][22][23] Table I includes additional data on crossover temperatures. Figure 5 shows the drag ratio is also affected by different dissociation rates for La, Nd, Gd and Y in Mg. For these solutes, association and dissociation rates are faster than reorientation, and positive drag ratio results from an "outer" vacancy ring network around the solute-similar to the behavior in BCC and FCC lattices [65,66].…”

“…supplemental material). The climbing-image nudged elastic band method with one intermediate image determines transition state configurations and energies [45], and harmonic transition state theory [46] with the hopping atom approximation [47,48] [20][21][22][23] with our complete dataset [55].…”

“…Magnesium alloys may substitute for aluminum and steel in aerospace and automotive industries with their higher specific strengths [9][10][11]. The growing interest in magnesium has driven experimental [12][13][14][15][16][17][18][19] and computational [20][21][22][23] studies of transport coefficients of the common Al and Zn solutes that improve strength and rare earth elements that improve ductility. Transport coefficients are fundamental inputs for models at the length and time scales of microstructure evolution.…”