Nanocrystalline nickel was prepared by a planetary ball milling apparatus working in a vacuum of 10−4Pa 10 −4 Pa in the 150–300 K temperature range. The kinetic of the milling process and the microstructure evolution upon annealing were followed by x-ray diffraction and mechanical spectroscopy measurements. It was observed that thermal annealing up to 600 K induces a strong reduction of the internal strains without significant grain growth. Measurements of elastic energy dissipation and dynamic elastic modulus as a function of temperature showed that in the nanocrystalline samples, anelastic relaxation processes occur, with the activation energy of grain boundary diffusion. A systematic study of the magnetic field dependence of the dynamic modulus (ΔE (ΔE effect) revealed a correlation between the ΔE ΔE magnitude and the strain values obtained by x-ray diffraction analysis.
Bonetti, E., Campari, E.G., Pasquini, L., Sampaolesi, E. (1998). Microstructure-related anelastic and magnetoelastic behavior of nanocrystalline nickel. JOURNAL OF APPLIED PHYSICS, 84(8), 4219-4226 [10.1063/1.368639].
Microstructure-related anelastic and magnetoelastic behavior of nanocrystalline nickel
Campari, E. G.Secondo
Investigation
;Sampaolesi, E.Ultimo
Investigation
1998
Abstract
Nanocrystalline nickel was prepared by a planetary ball milling apparatus working in a vacuum of 10−4Pa 10 −4 Pa in the 150–300 K temperature range. The kinetic of the milling process and the microstructure evolution upon annealing were followed by x-ray diffraction and mechanical spectroscopy measurements. It was observed that thermal annealing up to 600 K induces a strong reduction of the internal strains without significant grain growth. Measurements of elastic energy dissipation and dynamic elastic modulus as a function of temperature showed that in the nanocrystalline samples, anelastic relaxation processes occur, with the activation energy of grain boundary diffusion. A systematic study of the magnetic field dependence of the dynamic modulus (ΔE (ΔE effect) revealed a correlation between the ΔE ΔE magnitude and the strain values obtained by x-ray diffraction analysis.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
