THE EFFECT OF QUENCHING AND NEUTRON IRRADIATION ON INTERNAL FRICTION OF ALUMINUM–5% MAGNESIUM ALLOY

1961 ◽  
Vol 39 (1) ◽  
pp. 119-132 ◽  
Author(s):  
W. G. Nilson
Keyword(s):  
Relaxation Time ◽  
Magnesium Alloy ◽  
Internal Friction ◽  
Neutron Irradiation ◽  
Low Frequency ◽  
Solute Movement ◽  
Solute Atoms ◽  
Damping Peak

Low frequency internal friction data were obtained on the alloy aluminium–5% magnesium to determine the effects of quenching and neutron irradiation on solute movement. A damping peak near 150 °C, attributed to stress-induced reorientation of solute atoms, was found to be shifted to lower temperatures by these treatments. This behavior corresponds to a reduction in relaxation time for the damping process, and is compatible with the idea that the solute atoms act as traps for vacancies.

INTERNAL FRICTION STUDY OF ALUMINIUM ALLOY CONTAINING 7.5 WEIGHT PERCENT MAGNESIUM

1965 ◽  
Vol 43 (7) ◽  
pp. 1347-1357 ◽  
Author(s):  
B. N. Dey ◽  
M. A. Quader
Keyword(s):  
Internal Friction ◽  
Room Temperature ◽  
Low Frequency ◽  
Weight Percent ◽  
Peak Shift ◽  
Kcal Mole ◽  
Solute Atoms ◽  
Damping Peak ◽  
Weak Damping ◽  
Friction Study

Low-frequency internal-friction data were obtained using the torsion pendulum for the aluminium −7.5 wt% magnesium alloy in order to study the effects of quenching and aging on solute atom movements. A damping peak near 120 °C, attributed to the stress-induced reorientation of solute atoms (Zener relaxation), was found to shift to 80 °C on quenching. The activation energy for the peak at 80 °C was found to be 22.3 ± 1.5 kcal/mole, about 3 kcal/mole less than that for the Zener peak. The peak shift was found to be due to movement of solute atoms involving divacancies with reduced relaxation time. Aging of the quenched alloy at room temperature for one day was found sufficient to eliminate the effect of quenching in reducing relaxation time.Another weak damping peak near 40 °C in the as-quenched alloy specimen, attributed to the relaxation involving solute clusters, was found to be more pronounced on aging at room temperature for 24 hours, thereby indicating formation of zones in the quenched alloy during aging at room temperature. It was inferred from the results that about 100 atomic jumps were required to complete the relaxation responsible for this peak.Grain-boundary peaks were also observed in the furnace-cooled and the water-quenched specimens.

Measurement of internal friction and shear modulus of aluminium-magnesium alloy after neutron irradiation at 78 K

1975 ◽  
Vol 24 (1) ◽  
pp. 13-18 ◽  
Author(s):  
K. Chountas ◽  
K. Papathanassopoulos ◽  
P. Andronikos ◽  
N. Kontoleon
Keyword(s):  
Magnesium Alloy ◽  
Internal Friction ◽  
Shear Modulus ◽  
Neutron Irradiation

Study of 14.9 MeV Neutron Irradiation Effects on Ni/GaN Schottky Contacts Using Low‐Frequency Noise Spectroscopy

2019 ◽  
Vol 217 (7) ◽  
pp. 1900701
Author(s):  
Yuan Ren ◽  
Leidang Zhou ◽  
Kang Zhang ◽  
Liang Chen ◽  
Xiaoping Ouyang ◽  
...  
Keyword(s):  
Neutron Irradiation ◽  
Low Frequency ◽  
Schottky Contacts ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Irradiation Effects ◽  
Noise Spectroscopy

Investigating the dielectric properties and low-frequency relaxation process of TlGaSe2 crystals

2017 ◽  
Vol 31 (12) ◽  
pp. 1750134 ◽  
Author(s):  
Oktay Samadov ◽  
Oktay Alakbarov ◽  
Arzu Najafov ◽  
Samir Samadov ◽  
Nizami Mehdiyev ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Relaxation Time ◽  
Constant Electric Field ◽  
Low Frequency ◽  
Constant Field ◽  
Impedance Spectra ◽  
Ionic Contribution ◽  
Frequency Relaxation ◽  
Average Relaxation Time ◽  
Diagram Analysis

The dielectric and impedance spectra of TlGaSe2 crystals have been studied at temperatures in the 100–500 K range in the alternating current (AC [Formula: see text]1 V). It has been shown that the conductivity of TlGaSe2 crystals is mainly an ionic characteristic at temperatures above 400 K. The well-defined peak at the frequency dependence of the imaginary part of impedance [Formula: see text] is observed in the 215–500 K temperature range. In a constant field, there occurs a significant decrease in electrical conductivity [Formula: see text] in due course. The ionic contribution to conductivity (76% at [Formula: see text]) has been estimated from a kinetic change in electrical conductivity [Formula: see text] under the influence of a constant electric field. The diagram analysis in a complex plane [Formula: see text] has been conducted by applying the method of an equivalent circuit of the substation. It has been determined that the average relaxation time of the electric module of the sample is [Formula: see text].

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