| FSW and VPPA are two welding methods commonly used in 2219 aluminum welding. In the production of the aerospace storage tank, the combination of two kinds of welding technology forms cross welding joint. But the research in this area is still less at the moment in domestic. Welding joints are often repaired due to the quality. For promoting the further studying of the FSW and VPPA, combining the project as a background, the influence of oxide film on cross joints of 2219 aluminum alloy by FSW-VPPA is studied in this paper.This paper designed antitheses test and careful analyzed the influence of oxide film on the seam appearance formability, microstructure, mechanical properties and welding defects. Research found that the more oxide film contents, the poorer the cross welding appears and the much more the typical of as-cast organization is not obvious. At the same time the existence of oxide film affects the crystallization and grain growth way of the cross welding. And the performance of microstructure is lower. Because of the impact of FSW, the microstructure is a little over-heating or even over-burning.The mechanical performance of the cross welding which was completely removed surface oxide film is lower, directional. The microhardness of cross welding appears "W" type, and the hardness value of the fusion area is lowest. This also verified fusion zone is the weakest area. Oxide film affects the mechanics properties of the cross welding through increasing the number of welding pores and second phase particles.It is also found in research there are many defects in the cross welding of which the main defect is gas pores. The distribution of defects is along the fusion in the line chainlike. Combined with the experiments, this paper proved that oxide film has important effect.
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