High flux pulsed reactor IBR-2 allows the study of local oscillations of p elements (O, N, C) in transition metal solid solutions by inelastic incoherent neutron scattering (IINS). In comparison with interstitial hydrogen atoms studied earlier, great sizes of interstitial p elements cause a strong repulsion around interstitials. A new type of metal atom local oscillations («splitting») arises from the nearest neighboring metal atoms due to increase of their force constants at the repulsion. Strong clustering of interstitials takes place in BCC-solid solutions. All this is close to radiation defects. Interactions of substitution (S) and interstitial (I) atoms differ strongly between p elements or hydrogen as interstitials. Local oscillations of p elements change weakly under such interactions for undersized substitution atoms. Only Fe-based alloys have strong S - I chemical interaction in Fe-Cr-N solid solution. A new lattice dynamic model of defect crystal was proposed. It shows a contribution of deformation interaction in total (deformation plus chemical) interactions. The model takes into account the influence of relaxations around interstitials on local oscillations. Some IINS experiments were explained by this model for lattice dynamics of interstitial solid solutions.

PDF (749 Kb)