THE INFLUENCE OF THIN SURFACE LAYERS OF MINERAL OILS ON THE DAMPING CAPACITY OF METAL SAMPLES

Low temperature peak on the internal friction curve for CoPt samples covered with the layer of mineral paraffin oils was found to be connected with the nature of surface layer. The temperature position of the peak is related to the melting point of the solidified oil and its height depends on the annealing temperature

THE INFLUENCE OF HYDROCARBON SURFACE LAYER ON THE INTERNAL FRICTION IN METAL SAMPLES

Nous avons étudié en fonction de la température la variation du frottement intérieur d'un composite constitué par un métal recouvert d'une couche d'hydrocarbure saturé. Le calcul de l'amortissement et du module de cisaillement de la couche a été réalisé à l'aide du modèle rhéologique de Maxwell. De plus nous avons obtenu la variation du temps de relaxation.The internal friction of metal and alloy samples covered with a thin layer of saturated hydrocarbon was measured using the torsion pendulum technique. An attempt was made to separate the internal friction and shear modulus of surface layer. The Maxwell rheological model of a layer was used for the description of experimental results. The temperature dependence of relaxation time was obtained

THE INFLUENCE OF PHASE TRANSFORMATION ON THE TEMPERATURE SPECTRUM OF INTERNAL FRICTION IN N18 K10M5T AND H10N7K10M5 STEELS

Nous présentons les résultats de l'application de la metode du frottement intérieur pour l'étude de la transformation martensitique dans deux aciers industriels fabriqués en Polonge : I - N18K10M5T, II - H10N7K10M5. Les températures caractéristiques ont été trouvées. Nous avons établi que la transformation atherme est dans l'acier I et la transformation izotherm dans l'acier II.In the present note the application of the internal friction method to the investigation of phase transformations in two types of Polish commercial steels /I - N18K10M5T, II - H10N7K10M5/ is presented. Our measurements allowed to evaluate the characteristic temperatures /Ms, Mf, Ac1, Ac3 / of phase transformations in both steels, as well as to indicate differences beetwen athermal martensite transformation in steel I and isothermal in steel II

Ɗ G EFFECT IN EQUIATOMIC Co-Pt ALLOY

The amplitude dependence of shear modulus in CoPt alloy / 50.4% at. Pt / in disordered, ordered and partially ordered state was investigated. The distinct minimum of modulus for shear strain amplitude γ = 3.10-4 observed only in the case of disordered alloy is due to magnetomechanical hysteresis and can be successfully described basing on Smith and Birchak theory

THE INTERNAL FRICTION OF VANADIUM-PHOSPHATE GLASSES DOPED WITH BaO AND SrO

The vanadium-phosphate glasses of chemical composition xBaO · (50-x) V2O5 · 50 P2O5 and xSrO · (50-x) V2O5·50 P2O5 x from 10 to 50 mol % were investigated using the torsion pendulum at the frequency range 0,7 ÷ 21 Hz and at temperatures between 120 and 650 K. The internal friction curve Q-1 /T/ reveals the low-temperature maximum connected with the electron relaxation between V+4 and V+5. The influence of BaO and SrO on the relaxation process is studied. The activation energy of this process increases from about 0,33 eV to 0,73 eV when x increases from 10 to 40 mol%. The low-temperature maximum slightly decreases and shifts to higher temperature when the con-tent of V2O5 decreases from 50 to 10 mol% and disapper in glasses without V2O5. The activation energies of internal friction low-temperature maximum are related to the activation energies for conductivity

INFLUENCE OF PLASTIC DEFORMATION ON INTERNAL FRICTION OF ALUMINIUM WITH OIL LAYER

Les spectres de frottement intérieur d'échantillons d'aluminium /99,999 %/ recouverts d'une fine couche d'huile dépendent du taux de déformation plastique de l'échantillon. Pour les échantillons recuits, le pic d'huile apparaît vers 205 K, la température de solidification de l'huile. La déformation plastique augmente le pic d'huile jusqu'à un taux de l'ordre de 4 % et crée un nouveau pic à plus haute température. Les résultats sont discutés en fonction de la nature de la couche superficielle.Low temperature internal friction spectra for Al sample (99.999) with thin parafin oil layer depend on the amount of plastic deformation in the metal. For annealed samples, single oil damping peak appears at melting temperature TP = 205 K. Plastic deformations up to 4% increases the oil maximum and creates a new oil peak at higher temperatures. Results are qualitatively discussed as a function of the nature of the surface layer

THE INFLUENCE OF STEARIC ACID MONOLAYERS ON THE INTERNAL FRICTION OF COPPER

The internal friction Q-1/T/, of Cu samples covered by monolayers of stearic acid has been measured. The layers were grown by Langmuir-Blodgett technique. The obtained Q-1/T/ spectra exhibit the characteristic maximum at about 210 K which increases with the increasing number of deposited layers. Additionally Q-1 has been measured for Cu lubricated with liquid stearic acid. Such prepared layer causes the Q-1 maxima at about 340 K