Speaker
Anna Nastruzzi
Description
Mechanical spectroscopy tests of high-purity nickel single crystal, with different lattice orientations, were performed in a forced oscillation pendulum, under high vacuum, at different frequencies. The temperature was varied from room temperature up to 500 °C. A periodic strain of amplitude 5x10−5 was applied. Internal friction spectrum reveals 3 mechanical loss peaks: P0 (transient peak), P1 and P2. P1 and P2 might be related to a motion of dislocations controlled by the migration of 2 types of jogs. Activation energies in the range 1.5 - 2 eV were found for both P1 and P2 peaks. These are comparable to pipe diffusion. TEM analyses confirmed the presence of dislocation jogs.
Author
Anna Nastruzzi
Co-authors
Prof.
Daniele Mari
(EPFL)
Dr
Manuel Pouchon
(EPFL/PSI)
Weibin Jiang
(CAS)
