Development of an atomic mobility database for liquid phase in multicomponent Al alloys: focusing on binary systems

Abstract

An atomic mobility database for binary liquid phase in multicomponent Al -Cu-Fe-Mg -Mn-Ni -Si-Zn alloys was established based on critically reviewed experimental and theoretical diffusion data by using DICTRA (Diffusion Controlled TRAnsformation)software. The impurity diffusivities of the elements with limitede xperimental data are obtained by meanso ft he least-squares method and semiempirical correlations. Comprehensive comparisons between the calculated and measured diffusivities indicate that most of the reported diffusivities can be well reproduced by the currently obtained atomic mobilities. The reliabilityo ft his diffusivityd atabase is further validated by comparing the simulated concentration profiles witht he measured ones, as well as the measured main inter-diffusion coefficients of liquid Al -Cu-Znalloys withthe extrapolated ones from the present binary atomicmobility database. The approach is of general validity and applicableto establish mobility databases of other liquid alloys.

Thermodynamic and kinetic analysis of the melt spinning process of Fe-6.5 wt.% Si alloy

“…Thermodynamic descriptions for the Fe-Si system are readily available in the literature [11,13]. In the kinetic part, the atomic mobility parameters of bcc_A2 and liquid were assessed by Wang et al [14,15]. However, those for the bcc_B2 and bcc_D0 3 phases are unavailable in the literature.…”

“…where ܳ : is a parameter describing the contribution of component i due to the chemical ordering of the p-q atoms on the two sublattices α and β, ‫ݕ‬ ఈ is the site fraction of component p on the α sublattice. As the atomic mobilities of bcc_A2 and liquid optimized by Wang et al [14,15] are compatible with the thermodynamic description by Lacaze and Sundman [13], the ordering contribution of the atomic mobility was also optimized using the thermodynamic factors computed from ref. [13] for consistency.…”

Microstructure Evolution and Growth Orientation of Directionally Solidified Mg–4 wt% Zn Alloy with Different Growth Rates

“…The thermophysical parameters of the Mg-4 wt% Zn alloy were referred in Refs. [24,25], k is 0.12, m is -6.04 K/wt% and D is 8.2 9 10 -8 m 2 /s. As shown in Fig.…”

Grain growth competition and formation of grain boundaries during solidification of hcp alloys

“…The Gibbs-Thomson coefficient was also calculated for pure Mg as Γ = γ 0 T M /(ρL f ), with a density ρ = 1.59 × 10 6 g/m 3 and a latent heat of fusion L f = 349 J/g [63]. The diffusion coefficient for Gd in liquid Mg was approximated as D ≈ D Mg r Gd /r Mg [64], considering Mg self-diffusion coefficient D Mg ≈ 6.3 × 10 −9 m 2 /s at T = 1000 K [65] and atomic radii r Gd = 233 pm and r Mg = 145 pm [66].…”