Sensitivity of Ti3Al + TiAl3 Two-Phase Alloys to the Cooling Rate and Discrepancy in Their Tensile Mechanical Properties

The solidification process is essential to the macroscopic properties of metallic materials. Nevertheless, the explanation of this phenomenon at the atomic level is quite incomplete. In the present investigation, molecular dynamics simulations were used to probe the structural evolution and atomic migration properties of Ti–Al alloys, one of the alloys frequently used in rapid quenching techniques, during cooling from 2000 to 300 K. The initial model we constructed was a Ti–Al alloy with different structures on the left and right parts, D0₁₉-Ti₃Al on the left and L1₂-TiAl₃ on the right, making the total Ti–Al element ratio about 1:1. In previous studies, the rapid solidification process was analyzed for a single structure of the Ti–Al alloy, and few quenching studies have been conducted for Ti–Al alloys with different structures. Therefore, we constructed Ti–Al alloys with different structures and analyzed the effect of cooling rate on Ti–Al alloys by analyzing the rapid quenching process at different cooling rates via energy, radial distribution function, atomic mean square displacement, and element concentration distribution. The types of Ti–Al alloys obtained after annealing were calculated using XRD in LAMMPS. Subsequently, the mechanical properties of different Ti–Al alloys were analyzed by uniaxial tensile mechanical tests to obtain the differences in mechanical properties between crystalline and amorphous Ti–Al alloys during the tensile process.