铝/钢预置Cu镀层激光搭接焊接头组织及力学性能

Microstructure and mechanical properties of laser overlap welded joints of aluminum/steel with pre-plated Cu coating

为研究以预置Cu镀层为中间层的铝/钢异种金属的激光焊接行为,在6061铝合金与DP590双相钢2种母材表面电镀Cu层,对预置Cu镀层的6061铝合金与DP590双相钢进行了激光搭接焊。利用扫描电镜、能谱仪、拉伸试验及显微硬度试验对接头的显微组织及力学性能进行了研究。结果表明,0.5 mm等厚的6061铝合金/DP590双相钢的预置Cu镀层激光搭接焊的优化工艺参数为激光单脉冲能量为10 J,脉宽为6 ms,频率为15 Hz,Cu镀层厚度为60μm,铝/钢搭接焊缝的抗拉强度为59.8 MPa。预置Cu镀层起到了阻隔作用,能够减弱铝/钢的直接扩散,有效抑制了Fe-Al硬脆性金属间化合物的形成,提高了焊缝的抗拉强度,降低了焊缝显微硬度。随着预置Cu镀层厚度的增加,铝/钢焊缝的熔合界面变得更为光滑。

In order to study laser welding behavior of aluminum/steel dissimilar metals with pre-plated Cu coating as intermediate layer,Cu coating was electroplated on the surface of 6061 aluminum alloy and DP590 duplex steel,and laser overlap welding of 6061 aluminum alloy and DP590 dual-phase steel with pre-plated Cu coating was carried out.Microstructure and mechanical properties of welded joints were studied by scanning electron microscope,energy spectrometer,tensile experiment and microhardness experiment.The results showed that the optimized welding parameters for laser lap welding of 6061 aluminum alloy/DP590 dual-phase steel with the same thickness of 0.5 mm were that laser single pulse energy was 10 J,pulse width was 6 ms and frequency was 15 Hz.Thickness of Cu coating was 60μm and tensile strength of aluminum/steel overlap weld was 59.8 MPa.The pre-plated Cu coating had a barrier effect,which could reduce direct diffusion of aluminum/steel,effectively inhibit formation of Fe-Al hard and brittle intermetallic compounds,improve tensile strength of the weld,and reduce microhardness of the weld.With the increase of thickness of pre-plated Cu coating,fusion interface of aluminum/steel weld became smoother.