焊接气孔缺陷对A7N01铝合金焊接接头腐蚀疲劳性能的影响

在不同环境湿度条件下制备了不同焊缝气孔率的A7N01铝合金焊接接头,并通过条件腐蚀疲劳强度和断口微观形貌研究气孔缺陷对焊接接头腐蚀疲劳性能的影响。结果表明,当焊接环境的湿度由常湿增至70%时,焊缝的平均气孔率由0.07%增大为0.16%,接头的条件腐蚀疲劳强度由110 MPa降为100 MPa,焊接气孔缺陷对A7N01铝合金焊接接头的腐蚀疲劳性能有明显影响。焊缝中的气孔会造成严重的缺口效应,引起应力集中,导致裂纹在气孔处优先萌生,并在应力和腐蚀介质的共同作用下形成沿晶与脆性疲劳条带的混合断裂形貌。

Influence of welding pore defect on corrosion fatigue property of welded joint of A7N01 aluminum alloy

The welded joints of A7N01 aluminum alloy with different weld porosities are prepared in environment with different humidity.The influence of pores defect on corrosion fatigue property of the welded joints is studied by the conditional corrosion fatigue strength test and the fracture morphology observation.The results show that the average porosity increases from 0.07％ to 0.16％ when the humidity enhances to 70％,and the conditional corrosion fatigue strength decreases from 110 MPa to 100 MPa.Pore defects obviously affect the corrosion fatigue property of welded joints of A7N01 aluminum alloy.The pores in welds will cause serious gap effect and stress concentration,which lead to the priority initiation of cracks near the pores.The cracks form mixed fracture morphology,which propagates along the crystal and fragile fatigue strips under the collective effect of stress and corrosion medium.