Effects of γ/γ interfaces in TiAl lamellae subjected to uniaxial tensile loading

Abstract

Molecular dynamics simulations are used to investigate the influence of γ/γ interfaces on the tensile deformation behavior of γ-TiAl lamellae. Yield strength, dislocation nucleation and propagation are discussed. Results in this work indicate that adjacent lamellae with PT (pseudo-twin) or RB (rotational boundary) interface can constrain each other by in-plane stress due to modulus misfit, thus the yield strength can be influenced. Interfacial excess volumes and excess energies are continuously measured in elastic regime. Reordering of excess volumes and excess energies occurs due to their sudden decrease in elastic regime and different dislocation nucleation sites can be attribute to the final excess volume prior to the yielding. Moreover, dislocations propagate through PT/RB interface in an indirect way while propagate through TT (true-twin) interface in a direct way.