Tension-compression asymmetry in Ni/Ni3Al interfaces: An atomistic investigation

Nickel-based superalloys are well known for their excellent mechanical properties under high thermal or mechanical extremes. Reliable predictions of deformation behavior becomes paramount in such cases. Since Ni/Ni3Al interface is the prime defect in Ni-based superalloy single crystals, this letter investigates the underlying deformation mechanisms in differently oriented Ni-Ni3Al interfaces using atomistic simulations. For in-plane loading along the interface, significant tension-compression asymmetry (TCA) is observed in yielding and the responsible deformation mechanisms at the inception of plasticity are illustrated. Additionally, in-plane yield surface is constructed through biaxial loadings of the material. Finally, a generalized flow equation is proposed to capture the observed asymmetric behavior for its potential use in the realm of higher length scales.