2219-O铝合金厚板搅拌摩擦焊接缺陷分析

Defects Analysis of Thick Plate of 2219-O Aluminum Alloy in Frictional Stirring Welding

针对14mm厚2219-O铝合金在不同的焊接参数条件下进行搅拌摩擦焊接(FSW),分析了FSW典型缺陷产生的原因,以及焊接参数和搅拌头形状对缺陷形成的影响。拉伸试验结果表明,有孔洞或隧道型缺陷的接头屈服强度、抗拉强度和伸长率分别比无缺陷的接头降低了9.9%、24.0%和60.6%;有缺陷的接头拉伸断口SEM照片显示为韧-脆混合型断裂,其隧道型缺陷处断口形貌为"类蜂窝状",氧含量较高,而无缺陷的则以韧性断裂为主。显微硬度试验表明有缺陷的焊缝显微硬度总体低于无缺陷的。

The frictional stirring welding (FSW) for 2219-O aluminum alloy with 14mm in thickness was performed with varied welding parameters. The origination of typical flaw in FSW and effects of welding parameters and welding joint on the flaw were approached. The results indicate that compared with those of joint without defects, the yield strength, tensile strength and elongation of joint with void or tunnel defects are decreased by 11%, 32% and 153%, respectively. SEM observation reveals that the ductility-brittleness fracture morphology of the joint with defects can be observed, in which the rupture morphology of joint with tunnel defects exhibits dimple morphology with high oxygen content, while the ductility rupture in the joint without defects can be observed. In addition, the microhardness of joint with defects is lower than that of ones without defects. The mechanical properties of the joint with defects were deteriorated.