ISSN:
1662-9779
Source:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Topics:
Physics
Notes:
Acoustic properties of polycrystalline Cr samples of 99.99 % purity are investigated atfrequencies of longitudinal vibrations f ~ 75 kHz and of bending vibrations at 0.6 〈 f 〈 1.5 kHzwhen thermocycling within the temperature interval 5 − 330 K. Special attention is paid to theacoustic anomalies in the vicinity of the magnetic phase transitions: the Néel point and the spin-fliptransition. In the as-received samples, a significant hysteresis of the acoustic properties has beenfound for the first time. The effect of heat treatments on internal friction and elastic properties ofchromium polycrystals is also investigated. The data obtained are compared with the effect of smallpreliminary deformation and а long-time ageing at room temperature on the ultrasound anomalies inCr single crystal. The observed behavior of the acoustic properties may be caused by changes in theantiferromagnetic domain structure in Cr polycrystals under the action of thermoelastic stressesarising from quenching, preliminary plastic deformation or thermocycling
Type of Medium:
Electronic Resource
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.137.43.pdf
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