Mechanical stability of lamellar microstructure in TiAl:an atomic-scale study

Abstract

Mechanical stability of lamellar microstructure in γ-TiAl has been studied, for the first time, from the perspective of three different γ/γ lamellar interfaces evolution at atomic scale via molecular dynamics simulations. Results indicate that small lamellar spacing promotes the formation of longitudinal twinning, thus influences the mechanical stability of TiAl lamellar structure. Pseudo-twin (PT) and rotational boundary (RB) lamellar interfaces transfer to each other while the true-twin (TT) lamellar interface migrates directly and annihilates resulting from interaction with longitudinal twinning during deformation. Therefore, compared with the TiAl lamellar structure with TT interface, structure with PT and RB interfaces exhibit higher mechanical stability.