论文部分内容阅读
7050铝合金固溶处理后经67%冷变形,在120℃一级时效时,冷轧引入的大量位错增加了样品强度,时效4 h样品的强度比T6状态样品提高12.6%.随时效时间增加,位错导致的不均匀形核的析出相粗化,样品的拉伸强度逐渐降低.但时效32 h样品的强度仍高于T6状态样品.冷轧后时效样品的晶界析出相与T6状态相比分布较为分散,并且随时效时间的增加逐渐粗化.120℃时效4 h的样品,经165℃二级时效处理,随时效时间的增加,样品中残留位错大量湮灭,晶内、晶界析出相尺寸均逐渐增大,导致样品的强度逐渐降低,而延伸率逐渐升高,165℃时效6 h样品的强度与T76样品相似.在135—180℃二级时效1 h的样品中的位错密度随温度的升高而减小,同时晶内、晶界析出相尺寸随温度的升高而增大,导致样品强度逐渐下降.
The cold deformation of 7050 aluminum alloy after solution treatment was 67%, and the first stage aging at 120 ℃ increased the strength of the sample by a large number of dislocations introduced by cold rolling. The strength of the sample aged 4 h was 12.6% higher than that of the T6 state sample. Increase, dislocation caused by uneven nucleation of the precipitated phase coarsening, the sample tensile strength decreased gradually, but the aging 32 h sample strength is still higher than the T6 state samples after aging precipitation grain boundary precipitation phase and T6 Compared with the aging time, the samples were gradually roughened.After aging at 120 ℃ for 4 h, the residual dislocations were largely annihilated with aging time at 165 ℃, The size of precipitated phase in the grain boundary gradually increases, resulting in the gradual decrease of the strength of the sample, while the elongation is gradually increased, the strength of the samples aged at 165 ℃ for 6 h is similar to that of the samples of T76.When the sample is aged at 135-180 ℃ for 1 h The dislocation density decreases with the increase of temperature, meanwhile, the precipitated phase size increases with the increase of temperature, which leads to the gradual decrease of the sample strength.