Measurement of the Zener relaxation in high-purity FeCr single crystals

Citation
M. Hirscher et al., Measurement of the Zener relaxation in high-purity FeCr single crystals, MATER T JIM, 41(1), 2000, pp. 82-86
Citations number
13
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Metallurgy
Journal title
MATERIALS TRANSACTIONS JIM
ISSN journal
0916-1821 → ACNP
Volume
41
Issue
1
Year of publication
2000
Pages
82 - 86
Database
ISI
SICI code
0916-1821(200001)41:1<82:MOTZRI>2.0.ZU;2-X
Abstract
In binary alloys the measurement of the so-called Zener relaxation may be u sed as a non-destructive method to determine the activation enthalpy of sel f diffusion. High-purity FeCr single crystals with a Cr content of 53 at % were prepared by containerless inductive zone melting under Ar atmosphere. The internal friction was measured between temperatures of 300 to 1200 K us ing an inverted torsion pendulum in the frequency range between 2 and SO Hz . A strong damping is observed below the Curie temperature of about 600 K d ue to domain wall motion. Above the ferromagnetic transition temperature a relaxation maximum occurs at about 920 K. The relaxation strength and the a ctivation parameters were determined for single crystals with (100), (110) and (111) orientation. The relaxation can be assigned to die stress-induced reorientation of short-range ordered Fe and Cr atoms, respectively. An ana lysis yielded an effective activation enthalpy of (2.95 +/- 0.3) eV showing no significant dependence on the crystal orientation. The orientation depe ndence of the relaxation strength and shear modulus indicates that jumps be tween nearest and next-nearest neighbor sites are involved. These results a re compared with results of self-diffusion measurements.