Effect of Heat Treatments and Small Addition of Fe on the Occurrence of Serration in Al-Zn Alloys

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 (T_Q), 398K to 853K, and tensile-tested at room temperature. Serration occurred more easily according as T_Q became lower and the aging time became shorter: in the case that T_Q=473K serration was observed even after aging for 2.6Ms, while in the case that T_Q=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.

• Periodical: Materials Science Forum (Volumes 706-709)
• Pages: 305-310
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.706-709.305
• Online since: January 2012
• Authors: Teruto Kanadani, Keiyu Nakagawa, Akira Sakakibara, Koji Murakami, Makoto Hino
• Keywords: Aging, Aluminium Alloy, GP Zone, Serration, Stress-Strain Curve, Vacancy

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