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与7055铝合金的传统热轧(CHR)对比,制定了新的两阶段热轧工艺(DHR),分别采用CHR和DHR对7055铝合金板材进行轧制,研究了DHR工艺对7055铝合金析出相和亚结构的影响,分析了DHR和CHR处理后合金组织、力学性能的差异.结果表明:增加预变形量可提高析出相的球化程度(改变析出相形貌)但不影响其面积分数;中间高温短时退火可形成大量有序排布的亚结构;后续进一步热轧过程中,仍存在的大量球形析出相钉扎位错和亚晶界,且随累积应变增大,小角晶界逐渐转变成大角晶界而使晶粒细化.采用最佳的形变热处理工艺(固溶+预变形(300℃,20%)+中间退火(430℃,5 min)+热变形(400℃,60%))可在保证高强度的同时使7055铝合金板材断后延伸率比CHR工艺提高约25%.
Compared with traditional hot rolling (CHR) of 7055 aluminum alloy, a new two-stage hot rolling process (DHR) was developed. The 7055 aluminum alloy sheet was rolled by CHR and DHR respectively. The effects of DHR on the precipitation of 7055 aluminum alloy, The results show that increasing the amount of pre-deformation can increase the degree of spheroidization of the precipitated phase (changing the morphology of the precipitated phase) but does not affect the area fraction of the alloy. A large number of ordered sub-structures were formed during the short-time annealing at intermediate temperature. In the subsequent hot-rolling process, a large number of spheroidal precipitates still exist in the dislocation and subgrain boundaries. With the increase of accumulated strain, (300 ℃, 20%) + intermediate annealing (430 ℃, 5 min) + hot deformation (400 ℃, 60 %)) Can ensure high strength at the same time make the 7055 aluminum alloy plate elongation after fracture than the CHR process increased by about 25%.