Ab initio molecular dynamics study on properties of TA15 alloy high-temperature melt

The properties of alloy high-temperature melt are critical in determining product quality in precision casting and additive manufacturing, and the ab initio molecular dynamics (AIMD) method demonstrates advantages in addressing challenges in obtaining the high-temperature melt performance of multi-component titanium alloys. AIMD simulations of the TA15 alloy melt were conducted at three temperatures (2,000 K, 1,900 K, and 1,800 K), yielding structural properties such as radial distribution functions, coordination numbers, and bond angle distribution functions, as well as dynamic properties including mean square displacement and velocity autocorrelation functions. Furthermore, the diffusion coefficients and viscosity of the alloy melt were calculated. Results indicate that, in the TA15 alloy melt structure, the Mo-Ti and V-Ti interatomic distances are smaller than Ti-Ti distance, while Zr-Ti distance is larger. The diffusion coefficients of elements follow the order: V>Ti>Al>Mo>Zr. Mo and Zr atoms move slower due to their larger atomic masses, whereas V atoms diffuse faster due to weaker backscattering compared to Ti. The diffusion of Al atoms is restricted by the strong interaction between Ti and Al, and multi-center interactions exist between Ti and Al. The viscosity of the TA15 alloy melt, obtained using the Green-Kubo method, is 3.44 mPa·s at 2,000 K, 3.77 mPa·s at 1,900 K, and 4.67 mPa·s at 1,800 K.