The effects of 20°C natural aging and 20% cold work on the strength of 2013 aluminum alloy Al-1.7Cu-1.0Mg-0.8Si-0.15Cr: mass% aged at 170°C for 8 h have been investigated. The strength of T6 samples slightly decreased with increasing the time of natural aging after solution heat treatment. Though the amount of precipitation hardening was lower than T6 specimens, the strength was improved by combination of natural aging and cold working, namely T8 temper. However, cold working just after

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... heat treatment resulted in lower precipitation hardening, and thus the T8 strength was lower than that of the specimens with prolonged natural aging after solution heat treatment. It is suggested that the lower precipitation hardening resulted from the heterogeneous distribution of the hardening precipitates formed on the microbands.