Embedded atom simulation of the B2 phase in Nb-Ti-Al

The B2 phase of Nb rich alloys in the Nb-Ti-Al system was simulated using the Embedded Atom Method. Two different alloy compositions were examined, Nb-15Al-10Ti at.% and Nb-15Al-40Ti. The minimum energy lattice parameters for these two different intermetallic compositions were calculated and found to be within 2% of those determined by first principles methods for similar compositions, The site occupancies in these ternary B2 intermetallics were determined and compare favorably to experimental values. The elastic constants of these intermetallics were also calculated from the simulations. Planar defects including APBs, twins, and free surfaces were also simulated, The average relaxed APE energies in the ternary Nb rich alloys were found to range from 163 mJ/m(2) to 31 mJ/m(2) for alloys of 15 at.% Al and 10 to 40 at.% Ti, in agreement with experimental studies. The elastic constants obtained for these alloys also agree well with first principle calculations and experimental values. The implications of the simulation results for the understanding of the mechanical properties of these alloys are discussed.