Thermoactivated dislocation motion in rolled and extruded magnesium: Data of the low-temperature acoustic experiment

0547734 - ÚFM 2022 RIV CH eng J - Journal Article
Pal-Val, P. - Vatazhuk, O. - Ostapovets, Andriy - Král, Lubomír - Pinc, Jan
Thermoactivated dislocation motion in rolled and extruded magnesium: Data of the low-temperature acoustic experiment.
Metals. Roč. 11, č. 10 (2021), č. článku 1647. E-ISSN 2075-4701
R&D Projects: GA MŠMT(CZ) 8J19UA037
Institutional support: RVO:68081723 ; RVO:68378271
Keywords : Acoustic properties * Dislocations * HCP metals * Low temperatures * Magnesium
OECD category: Condensed matter physics (including formerly solid state physics, supercond.); Condensed matter physics (including formerly solid state physics, supercond.) (FZU-D)
Impact factor: 2.695, year: 2021
Method of publishing: Open access
https://www.mdpi.com/2075-4701/11/10/1647

Acoustic properties (logarithmic decrement and dynamic Young’s modulus) of commercial grade magnesium have been measured in the temperature range 51–310 K. Two types of magnesium samples have been studied: polycrystalline magnesium rolled at room temperature and subjected to hot extrusion. It is shown that the amplitude dependences of the acoustic properties are due to the thermally activated breakaway of dislocations from weak pinning centers. Within the framework of the Indenbom-Chernov theory of thermally activated dislocation hysteresis, the bind-ing energy of the interaction between dislocations and defects was estimated. Furthermore, dependences of the activation energy and activation volume on the applied stress were obtained in the microplastic region. The temperature dependences of the dynamic Young’s modulus are obtained in the amplitude independent region in the temperature range of 51–310 K. Functional form of the Young’s modulus temperature dependences corresponds to the classical concepts of the effect of thermal excitation of electrons and phonons on the elastic properties of crystals. © 2021 by the authors. Licensee MDPI, Basel, Switzerland.
Permanent Link: http://hdl.handle.net/11104/0323915