阳极氧化对7075铝合金疲劳性能的影响

Effects of Anodizing Methods on Behavior of 7075 Aluminum Alloy

研究了铬酸与硫酸阳极氧化对7075铝合金疲劳性能的影响，结果显示，铬酸阳极氧化在△K较小时，能显著降低7075-T6铝合金在空气中疲劳裂纹扩展速率以及在3．5％NaCl溶液中的腐蚀疲劳裂纹扩展速率，而在ZXK较大时对疲劳裂纹扩展的速率几乎没有影响，却使腐蚀疲劳裂纹扩展速率明显增加。在实验室空气中经铬酸阳极氧化的铝合金的疲劳断口裂纹扩展的皱褶更为细致，腐蚀疲劳断口则几乎见不到裂纹扩展形成的辉纹。还发现△K在300-700N／mm^3／^2之间，硫酸阳极氧化使7057-T6铝合金疲劳裂纹的扩展速率增大，只是当△K较大时增加的幅度不是十分明显，却能在较宽的AK范围内显著降低铝合金腐蚀疲劳裂纹的扩展速率。

Chromic acid anodizing can reduce the rate of fatigue crack growth（FCG） in air and the rate of corrosion fatigue crack growth（CFCG） in 3.5% NaCl solution in the range of lower △K. As △K is larger, chromic acid anodizing hardly has an effect on the rate of FCG in air, whereas makes the rate of CFCG in 3.5% NaCl solution become increases the rate of FCG in air when lution is remarkably decreased in the slightly larger. Results show that sulfuric acid anodizing distinctly △K ween 300-700 N/mm^3/^2. The rate of CFCG in 3.5% NaCl so-whole scope of △K.