Al-Zn-Mg合金の二段時効について

概要

論文の詳細を見る
Two-step aging in Al-7 wt% Zn-2.13 wt% Mg was investigated by hardness measurement and transmission electron microscopy. Specimens were solution-treated at 470℃ for lhr, subsequently quenched into iced water and finally subjected to various heat treatments. The results obtained were as follow: The maximum hardness of the specimen aged at 170℃ after pre-aging at room temperature or 50℃ was about Hv140～150. In the case of the pre-aging at 80℃ or 120℃, the maximum hardness was about Hv 170. This hardness was superior to that by normal aging at 170℃ but was inferior to that by normal aging at 120℃. The hardness which had been increased due to pre-aging did not drop to the initial values as quenched, except the specimen pre-aged at room temperature for 10 min or 100 min. The hardness attained above Hv 170 by pre-aging at 120℃, decreased one-sidedly by second-step aging at 170℃.