โ Scribed by T.M Williams; G.M Leak
No coin nor oath required. For personal study only.
An inverted torsional pendulum has been used to study the high temperature damping of spectroscopically pure copper and aluminium.
Three separate damping peaks have been observed in copper at about 28O"C, 550ยฐC and 700ยฐC for a frequency about 1 c/s. Two damping peaks have been observed in aluminium at about 300ยฐC and 560ยฐC for a frequency about 1 c/s. These peaks correspond to the 280ยฐC and 700ยฐC peaks in copper.
Activation energies for the mechanisms giving rise to the three types of damping peaks have been estimated, and an explanation of the origin of the peaks is offered in terms of grain boundary migration, annealing twin migration and grain boundary sliding. PICS DE RELAXATION A HAUTE TEMPERATURE DANS LE CUIVRE ET L'ALUMINIUM On Btudie, B l'aide d'un pendule de torsion inverse, l'amortissement a haute temperature de cuivre et d'aluminium spectroscopiquement purs. On observe trois pies d'amortissement s&pares dans le cuivre, a environ 28O"C, 550ยฐC. et 700ยฐC pour une frequence d'environ 1 c/s. On observe deux pits d'amortissement dans l'aluminium 1 environ 300ยฐC et 560ยฐC pour une frequence d'environ 1 c/s. Ces pits correspondent aux pits 280ยฐC et 700ยฐC du cuivre. On fait une estimation des energies d'activation pour les mecanismes dormant naissance aux trois types de pits d'amortissement; on propose une explication de l'origine des pits en termes de migration de joints de grains, migration de macles de recuit et glissement des joints de grains. HOCHTEMPERATUR-RELAXATIONSMAXIMA IN KUPFER UND ALUMINIUM Mit einem umgekehrten Torsionspendel wurde die Hoch-temperaturdampfung van spektroskopisch reinem kupfer und Aluminium gemessen. In Kupfer wurden bei einer Frequenz van 1 c/s drei getrennte Diimpfungsmaxima bei 28O"C, 550 "C und 700ยฐC gefenden. Zwei Diimpfungsmaxima wurden in Aluminium bei 300 "C und 560 "C bei 1 c/s gefunden. Diese Maxima entsprechen denen bei 280 "C und 700 'C in Kupfer. Die Aktivierungsenergien fur die verschiedenen Dampfungsprozesse wurden abgeschatzt. Die Maxima werden mit Korngrenzenwanderung,
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