The cryogenic thermal conductivity of high-strength 7050 aluminum alloy subjected to the processes with different combinations of solution, aging and deep cryogenic treatment, was measured by a one-dimensional steady-state thermal conduction method. The microstructure evolution of this alloy after different treatments was also characterized to investigate the changes in thermal conductivity. The results showed that the thermal conductivity of aluminum alloy was approximately linearly reduced with the decrease of temperature in general. Under the effects of different treatments, it was found that the thermal conductivity at different temperatures was sharply decreased by 30% after solution. Deep cryogenic treatment further decreased the thermal conductivity when it was conducted after solution. However, the conduction of aging increased the thermal conductivity after solution or solution-deep cryogenic treatment. Intensive lattice distortion and abundant of point defects that enhanced the electro scattering were the main reasons for decreasing the thermal conductivity after solution. The relatively large size of Al-Cu precipitates and increased dislocation density contributed to the further decrease of thermal conductivity after deep cryogenic treatment. The precipitation of a large number of ultra-fine secondary phase particles after aging increased the thermal conductivity by sufficiently releasing the lattice distortion. This work also provided an efficient method for investigating the mechanisms of deep cryogenic treatment on aluminum alloy by studying the thermal conductivity at low temperatures.

采用一维稳态热导法测量了高强度7050铝合金在固溶，时效和深冷处理的不同组合下所经历的低温热导率。还对经过不同处理的这种合金的微观组织演变进行了表征，以研究热导率的变化。结果表明，一般而言，铝合金的导热系数随温度的降低呈线性下降。发现在不同处理的影响下，固溶后在不同温度下的热导率急剧降低了30％。在溶液中进行深低温处理后，其导热系数进一步降低。然而，固溶或深固溶深冷处理后，老化的传导增加了热导率。强化晶格畸变和大量点缺陷增强了电散射，这是降低固溶后热导率的主要原因。Al-Cu沉淀物相对较大，位错密度增加，导致深冷处理后的热导率进一步降低。老化后大量超细二次相颗粒的沉淀通过充分释放晶格畸变而提高了热导率。这项工作还提供了一种有效的方法，通过研究低温下的热导率来研究对铝合金进行深冷处理的机理。