Design and Development of B2 Ti50Pd50-xMx (M= Os, Ru, Co) as Potential High Temperature Shape Memory Alloys

Abstract

In this chapter, the stability and phase transformation of B2 Ti50Pd50-xMx (M = Os, Ru, Co) alloys are investigated using density functional theory. TiPd alloy can be suitable for high-temperature shape memory applications due to its martensitic transformation capability from B2 to B19 at 823 K. It was reported that the binary Ti50Pd50 alloy is mechanically unstable at 0 K. A partial substitution of Pd with Os, Ru, or Co is investigated to determine which alloy will have the best properties. The heat of formation, density of states, and mechanical properties were determined to check the stability. The heat of formation was found to decrease with an increase in Ru and Os concentrations (condition of stability), consistent with the density of states trend. This is in contrast to Co addition, which indicates that the thermodynamic stability is not enhanced (heat of formation increases). It was also found that an increase in Os, Ru, and Co content stabilizes the Ti50Pd50 with a positive elastic shear modulus (C′>0) above 18.25, 20, and 31 at.%, respectively. This book chapter will provide valuable insights to guide experiments in the design and development of alloys.