The effect of cryogenic treatment (CT) combined with solution and ageing treatment on the residual stress and microstructure of 7050 aluminium alloy was investigated. The relationship between residual stress and microstructure was discussed. The results showed that compared to solution–ageing treatment (SA), CT after solution and before ageing (SCA) exhibited lower level and higher uniformity of residual stress. The highest dimensional stability was also obtained by the process of SCA. It was found that CT induced the fine precipitates through the lattice contraction under cryogenic temperature. Furthermore, the execution of CT in advance would also promote the uniform distribution of precipitates in the subsequent ageing by releasing and homogenising the residual stress.

中文翻译：

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深冷处理对铝合金残余应力及显微组织的改性

研究了深冷处理(CT)结合固溶和时效处理对7050铝合金残余应力和显微组织的影响。讨论了残余应力与显微组织的关系。结果表明，与固溶时效处理（SA）相比，固溶后和时效前（SCA）的CT表现出较低的残余应力水平和较高的均匀性。SCA工艺也获得了最高的尺寸稳定性。发现CT在低温下通过晶格收缩诱导细小沉淀物。此外，提前进行 CT 还可以通过释放和均匀化残余应力来促进后续时效中析出物的均匀分布。