Abstract:
NbRu has a potential as a high-temperature shape-memory alloy (HTSMA) because it has
a martensitic transformation temperature above 1000 ◦C. However, its shape-memory properties
could be improved for consideration in the aerospace and automotive industry. The unsatisfactory
shape-memory properties could be associated with the presence of a brittle tetragonal L10 martensitic
phase. Therefore, in an attempt to modify the transformation path from B2→L10 in preference of
either B2→orthorhombic or B2→monoclinic (MCL), an addition of B2 phase stabiliser, titanium
(Ti), has been considered in this study to partially substitute niobium (Nb) atoms. The ab initio
calculations have been conducted to investigate the effect of Ti addition on the thermodynamic,
elastic, and electronic properties of the Nb50−xTixRu50 in B2 and L10 phases. The results showed
that the B2 and L10 phases had comparable stability with increasing Ti content. The simulated
data presented here was sufficient for the selection of suitable compositions that would allow the
L10 phase to be engineered out. The said composition was identified within 15–30 at.% Ti. These
compositions have a potential to be considered when designing alloys for structural application at
high temperatures above 200 ◦C.
