The shape memory effect and martensitic transformation in alloyed titanium nickelide

Conclusions

• 1. A change in direct and reverse martensitic transformation temperatures and also thermomechanical shape change for titanium nickelide depend on the nature of alloying elements. Alloying elements of group VA (V, Nb, Ta) lead to a small reduction or even an increase (with addition of tantalum) in these temperatures. In contrast, elements of groups VIA and VIIIA (Fe, Co, Cr) sharply reduce the transformation temperatures.

• 2. Alloys containing niobium have a positive martensitic transformation hysteresis A_S-M_S with all of the test concentrations both under load and without it.

• 3. Hot plastic deformation affects in different ways the martensitic points in relation to alloying element content and its nature: in slightly alloyed materials the M_S temperature is reduced, but in more highly alloyed materials it increases; the A_S point in alloys with iron and niobium is increased with plastic deformation.