First-principles study of Ti50Ru50-xYx (Y = Ni, Pd and Pt) with a prospect to induce SME on stable CsCl-type Ti50Ru50 phase

Abstract

AbstractMost CsCl-type intermetallics composed of group IV and VIII–XI transition metals have shape memory effect (SME), a phenomenon that occurs on a certain class of materials with an ability to undergo martensitic transformation (MT) during cooling. This advanced functional materials’ property is enabled by MT from high-temperature B2 phase of high symmetry to lower symmetry phases such as L10, B19 or B19’ upon cooling. Peculiarly, Ti50Ru50 with similar ordered B2 at high temperature remains ordered and stable with no phase transition down to room temperature. In this study, first-principles calculations based on density functional theory (DFT) are used to investigate the structural, thermodynamic and electronic properties of the stable Ti50Ru50 compound by systematically substituting part of the Ru atoms with ductile group 10 metal (Ni, Pd and Pt). This is an attempt to destabilizing B2 phase at 0 K through Ti50Ru50-xYx ternary alloying to promote MT that could yield SME. Graphical Abstract