Al-Ti

Abstract: Complex concentrated alloys (CCAs) are a new generation of metallic alloys composed of three or more principal elements with physical and mechanical properties that can be tuned by adjusting their compositions. The extensive compositional workspace of CCAs makes it impractical to perform a comprehensive search for a specific material property using experimental measurements. The use of computational methods can rapidly narrow down the search span, improving the efficiency of the design process. We carried out a high-throughput parameterization of modified embedded atom method (MEAM) interatomic potentials for combinations of Cu, Ti, Ni, Cr, Co, Al, Fe, and Mn using a genetic algorithm. Unary systems were parameterized based on DFT calculations and experimental results. MEAM potentials for 28 binary and 56 ternary combinations of the elements were parameterized to DFT results that were carried out with semi-automated frameworks. Specific attention was made to reproduce properties that impact compositional segregation, material strength, and mechanics.

Abstract: Interatomic potentials for the Al-Ti, Al-Ta, Al-Zr, Al-Nb and Al-Hf binary systems have been developed based on the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. The fundamental materials properties (structural, thermodynamic and elastic behaviors of different intermetallics) could be readily described with the potentials using molecular dynamic simulation (MD), in rational agreements with experimental or first principles data. The potentials are further utilized to develop an interatomic potential for the (TiZrNbHfTa)Al₃ high entropy intermetallic compound (HEIC), which open the door to understand atomic scale behavior of HEICs.

Abstract: An interatomic potential for the Ti–Al binary system has been developed based on the second nearest-neighbor modified embedded-atom method (2NN MEAM) formalism. This potential describes fundamental materials properties (structural, thermodynamic, elastic, defect, deformation and thermal properties) of Ti–Al alloys in good agreements with experimental or first-principles data. The transferability and applicability of the present potential to atomic-scale investigations for Ni-based superalloys or Ti–Al based alloys are demonstrated.

Abstract: Semiempirical interatomic potentials have been developed for Al, α−Ti, and γ−TiAl within the embedded atom method (EAM) formalism by fitting to a large database of experimental as well as ab initio data. The ab initio calculations were performed by the linearized augmented plane wave (LAPW) method within the density functional theory to obtain the equations of state for a number of crystal structures of the Ti-Al system. Some of the calculated LAPW energies were used for fitting the potentials while others for examining their quality. The potentials correctly predict the equilibrium crystal structures of the phases and accurately reproduce their basic lattice properties. The potentials are applied to calculate the energies of point defects, surfaces, and planar faults in the equilibrium structures. Unlike earlier EAM potentials for the Ti-Al system, the proposed potentials provide a reasonable description of the lattice thermal expansion, demonstrating their usefulness for molecular-dynamics and Monte Carlo simulations at high temperatures. The energy along the tetragonal deformation path (Bain transformation) in γ−TiAl calculated with the EAM potential is in fairly good agreement with LAPW calculations. Equilibrium point defect concentrations in γ−TiAl are studied using the EAM potential. It is found that antisite defects strongly dominate over vacancies at all compositions around stoichiometry, indicating that γ−TiAl is an antisite disorder compound, in agreement with experimental data.