Digitale Medien
s.l. ; Stafa-Zurich, Switzerland
Solid state phenomena
Vol. 137 (Mar. 2008), p. 129-136
ISSN:
1662-9779
Quelle:
Scientific.Net: Materials Science & Technology / Trans Tech Publications Archiv 1984-2008
Thema:
Physik
Notizen:
The influence of heat treatment on the amplitude dependence of internal friction in Fe -11 at. % Al alloys with carbon contents in the range 0.005 - 0.2 at. % has been studied using aninverted torsion pendulum in the temperature range 300 – 950 K and a vibrating reed apparatus atroom temperature. The specimens were annealed at 1273 K in vacuum and cooled down withdifferent cooling rates in order to obtain different degrees of order. It was found that ordering ishardly avoidable in Fe - Al alloys with Al contents 〉 11 at. %. Ordered alloys are characterised bylower damping capacity due to higher coercivity caused by additional pinning of magnetic domainwalls by antiphase boundaries. X-ray diffraction investigations indicate that water-coolingsuppresses ordering in Fe - 11 at. % Al alloys while cooling in air or in furnace provokes D03–typeordering. Slowly cooled specimens are characterised by higher damping capacity due to lowercoercivity than water cooled or plastically deformed specimens. The amplitude dependentmagneto-mechanical damping was determined as the difference between amplitude dependentdamping without and with saturating magnetic field (~ 20 kA/m). Magneto-mechanical dampingwas found to be proportional to the strain where the amplitude dependent damping is maximumand reciprocal to the coercivity and saturation polarisation. Cold rolling increases the coercivityand therefore decreases the magneto-mechanical damping. An increase of the grain size in theinvestigated samples by heat treatment leads to a qualitatively expected decrease of coercivity andtherefore to an increase of magneto-mechanical damping
Materialart:
Digitale Medien
URL:
http://www.tib-hannover.de/fulltexts/2011/0528/02/24/transtech_doi~10.4028%252Fwww.scientific.net%252FSSP.137.129.pdf
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