Influence of Neutron Irradiation at Low Temperature on Internal Friction and Bulk Modulus of Silver

Abstract

internal friction and the bulk modulus of silver were studied after irradiation a t 25 K with fast neutrons. The Frenkel defects produced by irradiation cause dislocation pinning and a consequent decrease in the Bordoni internal friction peak. With increasing irradiation dose the bulk modulus first increases, reaches a maximum and then decreases below its original value. The behaviour of the modulus with annealing up t o room temperature essentially corresponds to that of the residual electrical resistivity after low-temperatare neutron irradiation. A Frenkel defect concentration C F D gives rise to a relative dielastic modulus decrease AGjG which was determined to be AG/(G C F D ) = -33 f 9.Innere Reibung und Schubmodul von Silber wurden nach Bestrahlung bei 2 25 K mit schnellen Neutronen untersucht. Die durch die Bestrahlung erzeugten Frenkeldefekte bewirken Versetzungsverankerung und dadurch eine Verkleinerung des Bordoni-Maximums der Inneren Reibung und eine Erhiihung des Schubmoduls. Mit steigender Bestrahlungsdosis steigt der Schubmodul zuerst an, durchlauft ein Maximum und fallt dann wieder linter seinen Ausgangswert ab. Das Verhalten des Moduls hei der Erholung bis auf Raumtemperatur gleicht weitgehend dem des elektrischen Restwiderstandes nach Tieftemperaturbestrahlung init Neutronen. Eine Frenkeldefektkonzentration CFL) bewirkt eine relative dielastische Modulerniedrigung AG/G, fur die der Wert AG/(GcFD) = -33 $-9 ermittelt 1% nrde.

The mechanical energy loss in stressed and -irradiated polycrystalline aluminium

“…Irradiation produces strong dislocation pinning which is expected to make B 2 and B 1 nearly disappear. This behaviour has been reported by several workers (Niblett and Wilks 1956, Chountas et al 1972, Mercier et al 1975, Lauzier et al 1975, Mizubayashi 1977, Boudraz and Gotthardt 1980, Guenin et al 1971, Fantozzi 1971, Alnaser and Zein 1993, 1992.…”

The Bordoni internal friction peak in silver single crystals

“…Experimental investigations of the Bordoni peak in silver have been carried out by Bordoni et a1 (1960), Okuda (1963a,b), Mongy et al (1965), Mecs and Nowick (1968), Besson et al (1972) and Chountas et a1 (1972). Most of the work was performed on polycrystalline material, for which the authors estimate values of the activation energy for the Bordoni peak ranging from 0.09 5 0.015 eV (Chountas et al 1972) to 0.130 f 0.008 eV (Besson et a1 1972), very similar to that for polycrystalline copper. Mongy et al (1965) compressed a silver single crystal by 10% in a (110) direction, and then measured the ultrasonic attenuation in the (loo), ( 111) and (110) directions at frequencies of 10, 20 and 50 MHz.…”

Internal friction and electrical resistivity measurements in CU and AG alloys after neutron irradiation at low temperature

“…For Ag alloys, investigations by internal friction have not been performed until now, except for the experiment on pure Ag [4]. Few investigations by means of electrical resistivity measurements have been performed [5 to 101.…”