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Internal Friction Studies on Oxygen–Oxygen Interaction in Niobium. I. Experimental Results and Application of Previous Interpretations
Author(s) -
Weller M.,
Haneczok G.,
Diehl J.
Publication year - 1992
Publication title -
physica status solidi (b)
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.51
H-Index - 109
eISSN - 1521-3951
pISSN - 0370-1972
DOI - 10.1002/pssb.2221720115
Subject(s) - maxima , niobium , oxygen , relaxation (psychology) , debye , superposition principle , enthalpy , thermodynamics , atomic physics , chemistry , yield (engineering) , materials science , physics , metallurgy , quantum mechanics , organic chemistry , performance art , art history , art , social psychology , psychology
Abstract In order to further clarify the long‐lasting controversy on the origin of the broadening of the Snoek maxima of heavy solute interstitial atoms (C. N. O.) in the internal friction of b.c.c. metals due to an interaction between those atoms measurements were carried out on niobium with various oxygen contents (0.1 to 0.85 at%) by applying frequencies of about 1 Hz and about 1 kHz to identical specimens. The means activation enthalpy of relaxation as determined from the frequency shift of the peak temperatures turns out to be independent of the oxygen content, H m = (1.15 ± 0.01) eV. The maxima are rather symmetrically broadened and shifted to higher temperature with increasing oxygen content. They are analysed in terms of previously introduced models. The clustering model proposing a superposition of discrete Debye submaxima for O pairs, triplets, etc. does not give an adequate description of the total Snock maxima. Consequently, their broadening may only be accounted for by a continuous distribution of relaxation times. Attempts with empirical approaches, like Gaussian or Fuoss‐Kirkwood distributions, yield a better but still insufficient agreement with the measurements. This indicates that an appropriate physical model for the interaction of interstitial solute atoms in b.c.c. metals is required to match the experimental data with their precision reached now.