Effect of Fe and Cu doping on properties of TiNi Alloys

abstract

English

The effect of Fe and Cu on the martensitic transformation behavior and mechanical properties of TiNi alloys has been investigated by calculating of the lattice constants and elastic moduli of the B2 phase. The site preference for both doping elements has been studied as well. The calculations were performed using the coherent potential approximation implemented within the framework of the exact muffin-tin orbitals method. Our theoretical results show contraction of the lattice constant of TiNi with increasing concentration of Fe. Added Fe atoms will always occupy the Ni sublattice even in the alloys where Ti is in deficiency. On the other hand added Cu atoms will occupy the sublattice of element in deficiency. This result has been also confirmed by our XRD measurements. The calculated elastic constants allow us to predict the martensitic transformation temperature, because this temperature is correlated with the C44 elastic constant. The composition dependence of elastic moduli and stability of B2 structure is discussed on the basis of the electronic density of states and phonon density of states.

shape memory alloys; NiTi; doping; elastic constants; ab initio

ZELENÝ, M.; YIN, X.; MI, X.

31. 3. 2014

Deutsche Physikalische Gesellschaft e.V.

Bad Honnef

MM 37.2

MM 37.2

1

http://www.dpg-verhandlungen.de/year/2014/conference/dresden/part/mm/session/37/contribution/2