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采用高功率、高速激光焊的方法,实现了3 mm厚6061-T6/AZ31B异种金属对接接头的焊接。利用体视显微镜、扫描电镜及能谱仪对接头的宏观形貌、显微组织及成分、断口特征进行分析,并测试了接头的显微硬度和抗拉强度。结果表明,焊缝内部近镁侧焊缝区及镁侧熔合区存在大量Al_(12)Mg_(17)相,其余区域为α(Al)和Al_2Mg_3两相混合组织。金属间化合物的存在导致焊缝内部显微硬度明显高于两侧母材,接头的抗拉强度可达34 MPa,拉伸断裂位置在近镁侧焊缝区,为典型的脆性断裂。
The use of high-power, high-speed laser welding method to achieve 3 mm thick 6061-T6 / AZ31B dissimilar metal butt joint welding. The macroscopic morphology, microstructure, composition and fracture characteristics of the joints were analyzed by stereomicroscope, scanning electron microscopy and energy dispersive spectroscopy, and the microhardness and tensile strength of the joints were tested. The results show that a large amount of Al_ (12) Mg_ (17) phase exists in the weld zone near the Mg side and in the weld zone on the Mg side, and the rest is a mixed phase of α (Al) and Al_2Mg_3. The existence of intermetallic compounds results in the microhardness of the weld is obviously higher than that of the base metal. The tensile strength of the joint is up to 34 MPa and the tensile fracture location is near the magnesium weld zone, which is a typical brittle fracture.