| 摘要 |
An alloy containing in percentage by weight <TABS:1069982/C6-C7/1> but in which the Ag content may be increased to 0.8% (with corresponding increase in the 1% total maximum) if the Cu is reduced below 2.5% by at least as much as Ag exceeds 0.5%, is subjected to a series of cold rolling steps each of which involves 12-50% reduction, a recrystallization anneal e.g. at 360 DEG to 385 DEG C., for 6 to 8 hours being given after each step except the last. The sheet is then solution treated at 525 DEG -545 DEG C., for approximately 15 to 50 minutes, and is then quenched and artificially aged e.g. at 175 DEG to 210 DEG C., for 4 to 30 hours. Prior to solution treatment the sheet may be given a recovery anneal at 150 DEG to 300 DEG C., for 15 minutes to 3 hours, whereby an improvement in creep properties is obtained. Alternatively or additionally the cast rolling slabs may be homogenized at a temperature at or just below that of solution treatment for 10 to 48 hours. The sheet may be clad with commerically pure aluminium, with aluminium containing 0.8 to 1.2% of zinc, or with an alloy containing .Mg.0.4-1.4 .Si.0.2-1.3 .Mn.0-1 .Cr.0-0.3 .Zn.0.8-1.2 .Al.balance |
