DECONVOLUTION ANALYSIS TO DETERMINE RELAXATION TIME SPECTRA OF INTERNAL FRICTION PEAKS

On décrit une nouvelle méthode d'analyse des pics de frottement intérieur en fonction de la température. Elle permet d'obtenir une approximation du spectre des temps de relaxation responsables du pic. On montre que cette méthode, appelée analyse directe du spectre (DSA), s'applique à différents types de spectres : (i) elle fournit des approximations de certaines formes de spectre qui reproduisent la position, l'amplitude, la largeur et la forme avec une bonne précision, qui est de l'ordre de 10 % (ii) elle ne conduit pas à des approximations aléatoires de la forme spectrale des pics.A new method for analysis of an internal friction vs temperature peak to obtain an approximation of the spectrum of relaxation times responsible for the peak is described. This method, referred to as direct spectrum analysis (DSA), is shown to provide an accurate estimate of the distribution of relaxation times. The method is validated for various spectra, and it is shown that : (i) It provides approximations to known input spectra which replicate the position, amplitude, width and shape with good accuracy (typically 10 %). (ii) It does not yield approximations which have false spectral peaks

Analysis of anelastic relaxations controlled by a spectrum of relaxation times

Anelastic studies, although they have provided an important method for investigating the mobility of point defects in solids, have often been difficult to analyze when a continuous spectra of relaxation times controls the anelastic response. This paper describes a new method for obtaining accurate estimates of relaxation time spectra by direct analysis (without prior assumptions) of the data using a nonlinear regression method. Applications to internal friction and anelastic creep results are described with emphasis upon the internal friction technique. 5 references

Evaluation of anelastic evidence for interstitial solute binding in bcc metals

A Direct Spectrum Analysis (DSA) technique has been applied to key internal friction and elastic after-effect data which are involved in the controversy over the existance of interstitial clustering in the refractory metals. It is found that at relatively high interstitial solute concentrations some of the Snoek peak broadening is due to relaxations that are distinct from the main relaxation. This finding supports the view that interstitial solutes have an interaction that produces clusters of interstitials

EVALUATION OF ANELASTIC EVIDENCE FOR INTERSTITIAL SOLUTE BINDING IN BCC METALS

Une nouvelle technique d'analyse directe des spectres (DSA) a été appliquée aux résultats cruciaux de frottement intérieur et de trainage méchanique invoquis dans la controverse sur l'existence d'une agglomération des interstitiels dans les métaux réfractaires. On trouve que, pour les concentrations de solutés interstitiels relativement élevées, une partie de l'élargissement du pic de Snoek est due a des relaxations distinctes de la relaxation principale. Ce résultat renforce l'idée d'une interaction de solutés qui conduit à la formation d'amas d'interstitiels.A Direct Spectrum Analysis (DSA) technique has been applied to Key internal friction and elastic after-effect data which are involved in the controversy over the existance of interstitial clustering in the refractory metals. It is found that at relatively high interstitial solute concentrations some of the Snoek peak broadening is due to relaxations that are distinct from the main relaxation. This finding supports the view that interstitial solutes have an interaction that produces clusters of interstitials