为研究2219铝合金搅拌摩擦焊接头的裂纹扩展行为, 首先对搅拌摩擦焊接头进行常规拉伸试验和裂纹延性扩展试验, 分析了接头各区的P-V曲线和不同裂纹扩展长度下的裂纹尖端张开角(CTOA), 讨论了裂纹扩展抗力以及裂纹扩展的方向。结果表明: 在试验条件下, 接头各区的抗裂纹扩展能力均高于母材的, 焊缝中心、前进侧和回退侧热机影响区的抗裂纹扩展能力无显著差异; 接头组织和力学性能的不均匀使裂纹扩展方向具有不稳定性, 前进侧热机影响区的裂纹在扩展过程中具有跨越焊缝扩展的趋势, 焊缝裂纹在扩展过程中会向回退侧热机影响区偏转, 回退侧热机影响区和母材裂纹扩展的偏转角度较小。

In order to research the crack propagation behavior of friction stir welded joints of 2219 aluminum alloy, the tests on mechanical properties and ductile crack propagation of the joints were conducted. Based on the results of P-V curves in different areas of friction stir welded joints and the crack tip opening angle (CTOA) values at different crack lengths, the crack propagation resistance and the crack propagation direction were studied. The results indicate that the crack propagation resistance in different areas of weld joint of 2219 aluminum alloy was greater than that in base metal under the research conditions, and there were no obvious differences in crack propagation resistance at the center of weld seam, thermo mechanically affected zone (TMAZ) on advancing side and retreating side. The inhomogeneity of the microstructure and mechanical properties of the joints led the instability of crack propagation directions. the cracks in TMAZ of advancing side propagated in the direction of weld seam, and the cracks in weld seam deflected toward TMAZ of retreating side, and the cracks in TMAZ of retreating side and in base material propagated with minor deflection.