Short-range order, atomic displacements and effective interatomic ordering energies in TiN0.82

T. Priem , B. Beuneu , C.H. de Novion , A. Finel , F. Livet

The elastic diffuse neutron scattering of a TiN0.82 single crystal has been measured in thermodynamic equilibrium at 700, 800 and 900 °C. The diffuse intensity is maximum at the (1/2 1/2 1/2) type reciprocal lattice positions. Nitrogen vacancies are found to situate preferentially as third neighbours on the metalloid f.c.c. sublattice. Pair interaction ordering energies were calculated by mean-field approximation, Monte-Carlo simulations, and Cluster Variation Method ; the last two methods give very similar temperature independent pair energies : V1 ≃ 82 and V 2 ≃ 62 meV for first and second nitrogen neighbours respectively ; V3 and further interaction energies are very small. Titanium atoms are found to relax away, and nitrogen atoms to relax toward their first neighbour vacancies, by respectively 0.042 and 0.024 A.

Keywords: Monte Carlo methods; neutron diffraction examination of materials; potential energy functions; short range order; titanium compounds; vacancies crystal

Domains: Physics archives

T. Priem, B. Beuneu, C.H. de Novion, A. Finel, F. Livet. Short-range order, atomic displacements and effective interatomic ordering energies in TiN0.82. Journal de Physique, 1989, 50 (16), pp.2217-2242. ⟨10.1051/jphys:0198900500160221700⟩. ⟨jpa-00211056⟩