7050 aluminum alloy samples were subjected to 67% cold rolling (CR) deformation after solution treatment, and then were aged at 120℃. The dislocations introduced by the CR increased the strength of the samples. The strength of the sample aged at 120℃ for 4 h (CR4) increased by 12.6% compared to that of T6 sample. The strength of the 7050 samples decreased with increasing the aging time due to the coarsening of heterogeneously--nucleated precipitates. However, the strength of the sample aged at 120 ℃ for 32 h is still higher than that of the T6 sample. Furthermore, the size and particle interval of the grain boundary precipitates increased as the aging time increased. The CR4 sample was aged at 165℃ for different times. The strength of the samples decreased with increasing the aging time due to the annihilation of dislocations and the growth of the precipitates. The strength of the sample aged at 165 ℃ for 6 h is similar to that of T76 sample. In the CR4 sample aged at 135-180℃ for 1 h, the number of dislocations reduced and the size of precipitates increased with increasing the temperature, which results in a decrease in the strength of the samples.
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