IFIR   05409
INSTITUTO DE FISICA DE ROSARIO
Unidad Ejecutora - UE
artículos
Título:
The Modified Relaxation Time function: a novel analysis technique for relaxation processes. Application to high-temperature Molybdenum internal friction peaks
Autor/es:
C.L. MATTEO; O.A. LAMBRI; G.I. ZELADA-LAMBRI; P. A. SORICHETTI; J.A. GARCÍA
Revista:
JOURNAL OF NUCLEAR MATERIALS
Editorial:
Elsevier
Referencias:
Año: 2008 vol. 377 p. 370 - 377
ISSN:
0022-3115
Resumen:
The modified relaxation time (MRT) function, which is based on a general linear viscoelastic formalism,
has several important mathematical properties that greatly simplify the analysis of relaxation processes.
In this work, the MRT is applied to the study of the relaxation damping peaks in deformed molybdenum
at high temperatures. The dependence of experimental data from these relaxation processes with temperature
are adequately described by a HavriliakNegami (HN) function, and the MRT makes it possible
to find a relation between the parameters of the HN function and the activation energy of the process. The
analysis reveals that for the relaxation peak appearing at temperatures below 900 K, the physical mechanism
is related to a vacancy-diffusion-controlled movement of dislocations. In contrast, when the peak
appears at temperatures higher than 900 K, the damping is controlled by a mechanism of diffusion in the
low-temperature tail of the peak, and in the high-temperature tail of the peak the creation plus diffusion
of vacancies at the dislocation line occurs.