长期大气腐蚀对2A12-T4铝合金结构疲劳性能的影响

发布时间：2018-05-07 22:19

本文选题：铝合金 + 大气腐蚀　；参考：《航空学报》2015年07期

【摘要】：开展了2A12-T4铝合金平板试验件、螺栓干涉试验件和冷挤压后螺栓干涉试验件在海南万宁大气环境下暴露腐蚀7年、12年和20年后的疲劳试验,进行了试验件腐蚀形貌分析、断口形貌分析和断口附近的侧边损伤形貌分析,并讨论了结构裂纹萌生位置、结构断裂部位和寿命变化规律等疲劳特征的形成原因和机理。研究结果表明:平板试验件和冷挤压后螺栓干涉试验件在腐蚀20年后的疲劳寿命与腐蚀12年相比基本持平,而螺栓干涉试验件的疲劳寿命持续下降;在长期大气腐蚀环境下结构局部强度的衰减速度排序是:螺栓干涉强化部位未强化部位冷挤压后螺栓干涉强化部位;2A12-T4铝合金材料在L-S面中部的腐蚀敏感性与L-S面侧边和L-T面相比更弱;L-S面发生的沿晶腐蚀是疲劳开裂的主要萌生源,长期腐蚀后侧面密集损伤导致的能量分散是使腐蚀20年后平板试验件寿命与腐蚀12年相比无明显下降的主要原因。
[Abstract]:The fatigue tests of 2A12-T4 aluminum alloy plate test piece, bolt interference test piece and cold extruded bolt interference test piece were carried out after 7, 12 and 20 years of exposure corrosion under atmospheric environment in Wanning, Hainan Province. The corrosion morphology of the specimens was analyzed. Fracture morphology analysis and lateral damage morphology analysis near the fracture surface, and discussed the formation of fatigue characteristics, such as crack initiation location, structural fracture location and life change law, and the formation mechanism of fatigue characteristics. The results show that the fatigue life of the plate and cold extruded bolt interference specimens after 20 years of corrosion is basically the same as that of the 12 years of corrosion, while the fatigue life of the bolt interference test pieces continues to decline. The order of attenuation rate of local strength of structure under long-term atmospheric corrosion environment is as follows: corrosion sensitivity and L-S surface of Bolt Interferometric strengthening part after Cold Extrusion of Bolt Interferometric strengthening part in the middle of L-S plane The intergranular corrosion on the side edge is the main source of fatigue cracking, which is weaker than that on the L-T plane, and the intergranular corrosion on the L-S surface is the main source of fatigue cracking. The energy dispersion caused by extensive side damage after long term corrosion is the main reason that the life of the plate specimen after 20 years of corrosion does not decrease obviously compared with 12 years of corrosion.
【作者单位】：空军工程大学航空航天工程学院;
【分类号】：V252.2;;TG171

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