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采用光学显微镜(OM)、电子背散射衍射检验(EBSD)、晶间腐蚀及剥落腐蚀试验,研究了两种预回复工艺(工艺1:250℃×24 h+300℃×6 h+350℃×6 h+400℃×6 h;工艺2:250℃×24 h+300℃×6 h+350℃×6 h+400℃×6 h+450℃×6 h)对经强化固溶(470℃×2 h+480℃×2 h+490℃×2 h)和T76时效(121℃×5 h+153℃×16 h)处理后的7085铝合金挤压材微观组织及抗腐蚀性能的影响。结果表明,与未经预回复处理的合金相比,经预回复处理后的合金晶粒显著细化(从61.822μm分别下降到6.135μm与10.892μm)、晶界平均角度显著降低(从26.6°分别降低至14.2°和12.9°)、低角度晶界(1~15°)的数目百分数显著提高(分别从31.3%提高到74.4%与76.1%)、抗晶间腐蚀性能明显改善(最大腐蚀深度由152.8μm分别减少到127.8μm与83.3μm)、抗剥落腐蚀性能也得到显著改善。对比两种预回复工艺,经预回复工艺2处理后合金的晶粒尺寸较经预回复工艺1有所长大,其晶界平均角度较低、低角度晶界的数目百分数也较低,抗腐蚀性能也更好,相对更佳。
Two kinds of pre-recovery processes (Process 1: 250 ℃ × 24 h + 300 ℃ × 6 h + 350 ℃ × 2 h) were studied by optical microscope (OM), electron backscatter diffraction (EBSD), intergranular corrosion and exfoliation corrosion tests. 6 h + 400 ℃ × 6 h; Process 2: 250 ℃ × 24 h + 300 ℃ × 6 h + 350 ℃ × 6 h + 400 ℃ × 6 h + 450 ℃ × 6 h) × 2 h +480 ℃ × 2 h +490 ℃ × 2 h) and T76 aging treatment (121 ℃ × 5 h +153 ℃ × 16 h). The microstructure and corrosion resistance of 7085 aluminum alloy extruded material were studied. The results show that, compared with the alloy without pre-treatment, the grain size of the alloy after pre-recovery treatment is significantly refined (from 61.822μm to 6.135μm and 10.892μm, respectively), and the average grain boundary angle is significantly decreased (from 26.6 ° Decreased to 14.2 ° and 12.9 °, respectively). The percentage of low angle grain boundaries (1-15 °) increased significantly (from 31.3% to 74.4% and 76.1% respectively), and the intergranular corrosion resistance significantly improved (the maximum corrosion depth From 152.8μm to 127.8μm and 83.3μm, respectively), the anti-spalling corrosion performance has also been significantly improved. Compared with the two pre-recovery processes, the grain size of the alloy after pre-recovery process 2 is larger than that of pre-recovery process 1, the average grain boundary angle is low, the number of low-angle grain boundaries is also lower, Corrosion performance is better, relatively better.