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 1200 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 1200 mm/min, approaching 77.6%of the strength of base metal. This enhancement was mainly attributed to the formation ofθ′and X phases, as well as the suppression of Ω-phase precipitation by Cu segregation at grain boundaries.%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1200 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1200 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.
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