铝合金材料腐蚀形貌及裂纹扩展分析

Corrosion Morphology and Crack Growth Analysis of Aluminum Alloy Material

通过加速腐蚀试验,利用QUESTAR三维光学显微镜观察,将蚀坑看作是椭球形,其深度及宽度都符合幂函数的形式,都随腐蚀时间的增加而增加,但增加的速率都降低;腐蚀能显著降低试件的疲劳寿命,是疲劳裂纹形成的主要原因;AFGROW软件较好地拟合了腐蚀试件的裂纹扩展寿命,拟合误差较低,且所得的裂纹扩展寿命及临界裂纹长度比实际试验值都偏保守。

Aluminum alloy was tested with accelerated corrosion method.The corrosion pits were seen as ellipse balls and examined with QUESTAR three-dimensional optics microscope.The results showed that the depth and width of corrosion pits increasing with corrosion time and in according with power function,but the acceleration decrease;Corrosion can reduce the fatigue life of the materials significantly and is the main cause of fatigue crack formation and growth;AFGROW software can simulate crack growth life well and the error is low;the crack growth life and critical crack length obtained by AFGROW simulation are conservative than experiment values.