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采用电导率、抗腐蚀性能测试及透射电镜观察等手段,研究了回归再时效处理过程中回归加热速率(340,57及4.3℃.min-1)对7050铝合金组织与抗晶间腐蚀和应力腐蚀性能的影响.研究发现,回归加热速率对7050铝合金的抗腐蚀性能有显著的影响,在顾及合金的综合力学性能的情况下,中等回归加热速率能使合金具有较好的抗腐蚀性能.7050铝合金在中速(57℃.min-1)回归加热条件下,经适当地回归再时效处理后,晶间腐蚀最大深度为50μm,等级为3级,比在340℃.min-1和4.3℃.min-1回归加热速率条件下具有更好的抗腐蚀性能,其晶界析出相为较粗大的非连续颗粒,并有较宽的无沉淀析出带.
The effects of regressive heating rate (340, 57 and 4.3 ℃ .min-1) on the microstructure and intergranular corrosion resistance and stress of 7050 aluminum alloy were studied by means of electrical conductivity, corrosion resistance test and transmission electron microscope observation. The results show that the regressive heating rate has a significant effect on the corrosion resistance of 7050 aluminum alloy, and the medium regressive heating rate can make the alloy have good corrosion resistance, considering the comprehensive mechanical properties of the alloy. 7050 aluminum alloy at medium speed (57 ℃ .min-1) return to heating conditions, after appropriate regression re-aging treatment, the maximum intergranular corrosion depth of 50μm, grade 3, than at 340 ℃. Min-1 and 4.3 ℃. Min-1 under the conditions of return to heating rate has better corrosion resistance, the grain boundary precipitates are coarser non-continuous particles, and a wider precipitation-free zone.