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Lattice dynamics of the high temperature shape memory alloy Nb-Ru

S. M. Shapiro·G. Xu·G. Gu·J. Gardner·R. W. Fonda
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Abstract

Nb-Ru is a high temperature shape memory alloy that undergoes a Martensitic transformation from a parent cubic b-phase into a tetragonal b' phase at TM 900 C. Measurements of the phonon dispersion curves show that the [110]-TA2 phonon branch, corresponding in the q=0 limit to the elastic constant C'=1/2(C11-C12) has an anomalous temperature dependence. Nearly the entire branch softens with decreasing temperature as TM is approached. The temperature dependence of the low-q phonon energies suggests that the elastic constants would approach 0 as T approaches TM, indicating a second order transition. No additional lattice modulation is observed in the cubic phase.

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S. M. Shapiro, G. Xu, G. Gu, J. Gardner, R. W. Fonda. 2006-03-01. Lattice dynamics of the high temperature shape memory alloy Nb-Ru. https://doi.org/10.1103/physrevb.73.214114

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