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The simultaneous influence of both thermal and mechanical treatment was applied to produce a geometrically complex shaft from 51CrV4 steel. This special treatment led to the formation of adjacent microstructures, which were significantly different from each other. Specimens for structural studies and determination of mechanical and physical properties were cut from different locations on the produced shaft and tested in order to verify and understand the obtained functional gradation. It was found that the microstructural changes were accompanied by a change of mechanical and physical properties measured in terms of hardness, electrical resistivity, and internal friction. The Snoek–Koster peak was determined, and found to be strongly dependent on structure and dislocation density and their interactions with impurities.

The simultaneous influence of thermal and mechanical treatment was applied to produce a geometrically complex shaft from 51CrV4 steel leading to the formation of microstructures which were significantly different from each other. These microstructural differences were accompanied by a local change of mechanical properties in terms of hardness, electrical resistivity and especially internal friction. The Snoek-Koster peak was recognized and analyzed in the structure of this steel.

The simultaneous influence of both thermal and mechanical treatment was applied to produce a geometrically complex shaft from 51CrV4 steel. This special treatment led to the formation of adjacent microstructures which were significantly different from each other. It was found that these microstructural changes were accompanied by a change of mechanical properties in terms of hardness, electrical resistivity and especially internal friction. Specimens for structural studies and study of mechanical and physical properties were taken out from different places of the produced shaft and tested in order to verify and understand the obtained gradation. The significant variations in properties could be explained in terms of structure and dislocation behaviour under applied cyclic stress using mechanical spectroscopy technique. The cold-work (Snoek-Köster) peak was recognised and analysed in the structure of this steel.

Internal friction (IF) in severely deformed Fe-26Al and Fe-26Al-5Cr (at. %) alloys based on the Fe3Al intermetallic compound has been studied in a temperature range from −180 to 650°C. A group of low-temperature IF maxima have been detected in the temperature range from −130 to 100°C at a frequency of 1.4–2.2 kHz. A comparative analysis of the revealed peaks has been carried out for Fe3Al both with and without chromium. The thermal stability of some IF maxima which form a group of low-temperature peaks in the severely deformed state has been studied. The activation energies for the maxima detected have been evaluated. An assumption has been made about the dislocation-related mechanism of the peak origin, some of which appear to be of the Hasiguti type. Within the framework of this assumption, the height and stability of some IF maxima in the Fe-26Al-5Cr alloy, as compared to those in the Fe-26Al alloy, can be explained by increasing mobility of dislocations (dislocation segments) due to alloying with chromium.

Low-temperature anelasticity related to dislocations and point defects in bcc Fe–26 at.% Al and in two hcp titanium alloys, severely deformed by high-pressure torsion, has been studied by mechanical spectroscopy. Up to five peaks have been observed; at least some of these can be classified as Hasiguti peaks. The stabilities of the internal friction peaks against heating are different. Mechanical spectroscopy is a useful tool to study the early annealing stages of severely plastically deformed alloys.

Anelastic effects in ternary Fe–Al–Si alloys at elevated temperatures (from 400 to ∼700 °C) have been studied by mechanical spectroscopy. The contributions of several damping mechanisms (high temperature background, Zener and grain boundary relaxations), which are sensitive to the structural state in the temperature range studied, are analysed. The structure of the alloys was examined by different methods. The results of computer analyses of the experimental data justify the superposition of several relaxation processes. Parameters of the Zener relaxation in two ternary Fe–Al–Si alloys are determined: the peak temperature is about 545 °C ( f ≈ 2 Hz); the mean value of the activation energy of the Zener relaxation is about 2.54 eV.

Low temperature dislocation- and point defect-related anelasticity in high pressure torsion (HPT) deformed metallic materials bcc Fe-26Al, fcc Fe-36Ni, hcp Ti is studied by mechanical spectroscopy. Internal friction (IF) peaks, which correspond to these phenomena, have different stability against heating. Up to five IF peaks are recorded, at least some of these peaks can be classify as Hasiguti peaks. Mechanical spectroscopy gives a useful tool to study early stages of severely plastic deformed alloys study.

Anelastic effects caused by carbon and vacancy diffusion in Fe3Al based alloys with and without strong carbide forming elements (Ti and Nb) are investigated by internal friction measurements. The decrease of the Snoek peak in Fe–26Al–2Ti and Fe–26Al–0.3Nb alloys with respect to the Fe–26Al alloy is related to a decrease in the amount of interstitially dissolved carbon (C). The so-called X peak, which is observed in the Fe–26Al alloy, also almost disappears after alloying. In order to elucidate the vacancy contribution to the origin of the X peak radiotracer measurements of 59Fe diffusion were performed. The results indicate that the change in the interstitially dissolved C concentration is the main reason of the observed changes in the X peak, although a certain influence of Ti and Nb alloying on the total vacancy concentration may be deduced from the diffusion study.

Temperature dependent internal friction (TDIF) spectra in Fe–(25–26)at.%Al alloys were studied using different mechanical spectroscopy techniques in a wide range of vibrating frequencies from 0.1 Hz to 1 kHz. Four relaxation peaks are observed (D, S, X, Z peaks), at least two of them (D, X) have not been reported earlier in Fe3Al intermetallic compounds. The nature of these peaks is discussed. Special emphasis is put in this paper on the instability of the Fe–Al structure with respect to heating during TDIF measurements.