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采用光学显微镜、透射电子衍射和扫描电子衍射显微分析技术,结合力学性能检测和电导率测定的方法,研究双级固溶温度和时间对7A55铝合金板材力学性能的影响。结果表明:最佳双级固溶制度为450℃,90 min+485℃,40 min。采用该固溶制度经120℃,24 h时效后,板材的拉伸力学性能达到σb=648.4 MPa,σ0.2=629.6 MPa及δ=11.9%。第一级固溶制度是影响板材力学性能的主要因素,最佳固溶温度为450℃。在450℃进行第一级固溶后,样品发生了较强的回复,由于降低了再结晶驱动力,第二级高温固溶在获得较高的合金元素过饱和度的同时,仅发生较少的再结晶,从而在随后的时效过程中产生更高的析出强化效应。
The effects of two-stage solid solution temperature and time on the mechanical properties of 7A55 aluminum alloy sheets were investigated by optical microscopy, transmission electron diffraction and scanning electron microscopy (SEM), combined with mechanical properties testing and conductivity measurement. The results showed that the optimum two-stage solution system was 450 ℃, 90 min + 485 ℃, 40 min. Tensile mechanical properties of the sheet reached σb = 648.4 MPa, σ0.2 = 629.6 MPa and δ = 11.9% after aging at 120 ° C for 24 h. The first-order solution system is the main factor that affects the mechanical properties of the sheet. The optimum solution temperature is 450 ℃. After the first solid solution at 450 ℃, the sample has a strong recovery, due to lower recrystallization driving force, the second high-temperature solution to obtain high alloying element supersaturation at the same time, only less Recrystallization, resulting in a higher precipitation strengthening effect in the subsequent aging process.