The precipitation of Ag from a super-saturated Pb-0.038 at% (0.02 mass%)Ag solution was followed by measuring the resistivity change on aging between 195 K and 513 K after quenching from 558 K. During the isochronal aging (45 s), the resistivity decreases in two different temperature-ranges: A, below 283 K; and B, 283-423 K. The resistivity decays in two stages (IA and IIA) with the isothermal aging in the range A. In the stage IA the reaction is of quadratic with an activation energy 37.7± 3.0 kJ/mol. During the isothermal aging in the range B, the decay occurs in a single stage (IB), the reaction of which is of first-order with an activation energy 50.2± 2.0 kJ/mol.
These results suggest that the Ag transport during precipitation is controlled by the movement of silver interstitials in the range A and by that of interstitial-vacancy pairs in the range B.
(Received April 28, 1982)
* Department of Metallurgical Engineering, College of Engineering, University of Osaka Prefecture, Sakai 591, Japan.
** Graduate School, University of Osaka Prefecture, Sakai 591, Japan. Present address: Mitsubishi Metal Corporation, Osaka 530, Japan.
© 2002 The Japan Institute of Metals
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