Viscoelastic and quasi-solid properties of $\rm Ni$-containing binary metal melts

This paper investigates the viscoelastic and quasi-solid state properties of nickel-containing binary metal melts in a wide temperature range, including the region of the equilibrium liquid phase and supercooled melt. The results of experimental measurements on viscometry and the molecular dynamics simulation results are compared in order to refine the data on viscosity and identify the features of the quasi-solid state behavior in various nickel-containing metal melts. The simulation results for the concentration and temperature dependences of viscosity are in close agreement with the experimental data. It is established that a significant increase in viscosity is observed at nickel concentrations of $x_{\mathrm{Ni}} = 60$–$80\%$ and $30$–$50\%$ for $\mathrm{Al}_{(100 - x)}\mathrm{Ni}_x$ and $\mathrm{Fe}_{(100 - x)}\mathrm{Ni}_x$ melts, respectively. In addition, in the region of low concentrations $(x_{\mathrm{Ni}} \sim 5\%)$, pronounced features are observed both in shear and kinematic viscosity for iron-nickel melts. The elastic properties are analyzed in detail based on the numerical calculations of the bulk compression and shear moduli, Poisson's ratio, and Young’s modulus. It is shown that with a change in the concentration of nickel in $\mathrm{Fe}_{(100 - x)}\mathrm{Ni}_x$ and $\mathrm{Al}_{(100 - x)}\mathrm{Ni}_x$ systems, the elastic moduli change by factors of two and three, respectively. The calculated values of the concentration dependences of the longitudinal and transverse sound velocities show a correlation with viscosity. It is found that at concentrations of $x_{\mathrm{Ni}} \le 60\%{,}~\mathrm{Fe}_{(100 - x)}\mathrm{Ni}_x$ melts are characterized by more pronounced solid-like properties compared to $\mathrm{Al}_{(100 - x)}\mathrm{Ni}_x$ melts.