用拉伸试验机、疲劳试验机、扫描电镜等对激光焊接6156-T4铝合金对接接头和T型接头的拉伸性能、疲劳性能和断口形貌进行了对比研究。结果表明：对接接头的拉伸性能接近于母材的，T型接头的抗拉强度较母材的有一定程度的降低，对接接头的疲劳强度明显高于T型接头的；对接接头疲劳断口位于热影响区，T型接头的断口穿过热影响区和母材；两种接头疲劳裂纹均萌生于应力集中较为严重的焊趾部位，以近似半椭圆的形状沿厚度方向扩展直至接头断裂。

The tensile property, fatigue property and fracture morphology of the laser welded butt joint and T-joint of 6156-T4 Al alloy were researched and compared using the tension testing machine, fatigue tester, scanning electron microscope, etc. The results show that the tensile property of the butt joint was close to that of the base metal, while the tensile strength of T-joint decreased to a certain extent comparing to that of the base metal. The fatigue strength of the butt joint was obviously higher than that of the T-joint. The fatigue fracture of the butt joint was in the heat affected zone while that of the T-joint was across the heat affected zone and base metal. The fatigue cracks of the two joints initiated from the weld toe, at which the stress concentration was relatively serious, and then propagated in a shape of approximate semi-ellipse along the plate thickness direction until the joint fracture.