焊接速度及焊后时效处理对Al-Cu-Mg-Ag合金电子束焊接接头性能的影响

通过拉伸测试、扫描电镜(SEM)、能谱分析(EDS)、透射电镜(TEM)和金相显微镜(OM)等手段, 研究了焊接速度以及焊后时效处理对Al-Cu-Mg-Ag合金电子束焊接接头性能的影响。结果表明: 随焊接速度提高, 焊接接头强度呈先上升后下降的趋势, 并在焊接速度1 200 mm/min时获得最大值358 MPa；焊后时效处理可以提升焊接接头抗拉强度, 其中焊接速度为1 200 mm/min时的焊接接头抗拉强度最大, 可达412 MPa, 为母材强度的77.6%。焊后时效合金性能的提高主要得益于θ'和X相的析出, 而焊缝熔合区晶界处Cu元素的偏析抑制了Ω相的析出。

Effects of Welding Speed and Post-weld Aging Treatment on the Properties of Electron Beam Welded Al-Cu-Mg-Ag Alloy

Effects of welding speed and post-weld aging treatment on the properties of electron beam welded Al-Cu-Mg-Ag alloy were investigated by tensile testing, scanning electron microscopy(SEM), energy dispersive spectroscopy(EDS), transmission electron microscope(TEM) and optical microscopy(OM). Results showed that with the increasing of welding speed, the tensile strength showed a downward trend after an initial rise, reaching  the maximum(358 MPa) at the welding speed of 1 200 mm/min. It is also found that the tensile strength of welding joints was enhanced by a post-weld aging treatment, up to the maximum(412 MPa) at the welding speed of 1 200 mm/min, approaching 77.6% of the strength of base metal. This enhancement was mainly attributed to the formation of θ' and X phases, as well as the suppression of Ω-phase precipitation by Cu segregation at grain boundaries.