固溶处理后冷轧变形7050铝合金时效工艺研究

来源期刊：金属学报2010年第5期

论文作者：王东 马宗义

文章页码：581 - 588

关键词：7050铝合金； 冷轧； 时效工艺； 力学性能； 显微组织

Key words：7050 aluminum alloy； cold rolling； aging process； mechanical property； microstructure

摘    要：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.

Abstract: 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.