Monte Carlo simulation of thermophysical properties of binary Co–Gd liquid alloys

• The temperature- and composition-dependent surface tension was obtained.
• The viscosity and diffusion coefficient were deduced from the data of surface tension.
• The possible reasons of the variation of the thermophysical parameters are elucidated.

Monte Carlo method with EAM potential is applied to simulate the thermophysical properties of the liquid Co–6.7, 10.5, 16.8, 22.2, 25.0 , and 33.3 at%Gd binary alloys. With the increase of the content of Gd, the simulated surface tension at the melting temperature decreases from 1.422 to 1.293 N/m, whereas the simulated temperature coefficient of surface tension rises from 1.36 × 10−3 to 1.84 × 10−3 N m−1 K−1. Based on the simulated surface tension, the viscosity and diffusion coefficient within the temperature range from 1300 to 2000 K are deduced. The dependence of viscosity on the temperature and the alloy composition has been obtained. The solute diffusion constant changes as a quadratic function of content Gd. The diffusion activation energy varying with the alloy composition is discussed. The calculation results quantitatively indicate that the liquid fluidity increases with the Gd content. Our results might provide the necessary thermophysical parameters which could be used in designing the microstructure and magnetic properties in Go–Gd system.