Affiliation:
1. Okayama University of Science
2. Okayama University
3. Industrial Technology Research Institute of Okayama Prefectural Government
Abstract
The effect of heat treatment conditions and small addition of Fe on occurrence of serration in Al-Zn alloys was investigated. Specimens were aged for various times up to 5Ms at 293K or 273K after quenching from various temperatures (TQ), 398K to 853K, and tensile-tested at room temperature. Serration occurred more easily according as TQbecame lower and the aging time became shorter: in the case that TQ=473K serration was observed even after aging for 2.6Ms, while in the case that TQ=773K serration did not occur irrespective of aging conditions. Serration was also recognized when the specimens were furnace-cooled from 773K to room temperature. Thus, for the binary alloy serration was observed only when the aging period was short enough, but addition of Fe to the binary alloy prolonged the aging period where serration could be recognized. Aging rate measured by hardness was remarkably retarded with the increase of Fe addition. These results together with those obtained by the electrical resistometry suggest that the serration in Al-Zn alloys occurs in the early stage of aging where small GP zones or solute clusters are formed.
Publisher
Trans Tech Publications, Ltd.
Subject
Mechanical Engineering,Mechanics of Materials,Condensed Matter Physics,General Materials Science