铜薄膜作中间层的镁铝扩散焊接

采用磁控溅射技术在变形镁合金表面沉积铜薄膜,将其作为中间层对变形镁合金和硬铝合金进行了低温扩散焊接研究.利用超声波显微镜、X射线衍射、扫描电镜、电子探针等对焊接接头界面区域的显微结构及物相等进行了研究.研究结果表明,在镁合金基体上沉积的Cu薄膜主要以(111)、(200)晶向上生长,薄膜表面平整、均匀、致密；在扩散焊接工艺条件焊接温度T=455℃、保温时间t=90 min、压力P=3 MPa下获得了质量较好的Mg/Al焊接接头.焊接接头界面区域由铝镁原子比分别为3∶2,1∶1,12∶17三层镁铝系金属间化合物构成,接头断裂破坏发生在镁铝系化合物层,断口呈现明显的脆性断裂特征.

Diffusion bonding of magnesium alloy and aluminum alloy using copper film as interlayer

MB2 magnesium alloy and LY12 aluminum alloy were successfully jointed through diffusion bonding method at quite low temperature by using Cu film as interlayer which was deposited on MB2 alloy surface by Magnetron Sputtering technique.Scanning Acoustic Microscopy,Scanning Electron Microscope,X-Ray Diffraction,Electron Probe Micro Analyzer were used to investigate the microstructures and phases in the interfaces of the joints.The experiment results show that smooth and dense Cu film grew up in(111),(200) crystal orientation on MB2 maganesum alloy substrate.High quality MB2/LY12 joint are prepared under the diffusion bonding process:temperature of 455 ℃,holding time for 90 min,pressure of 3 MPa.The joint interfaces consist of three different Mg-Al intermetallic compounds which are Al3Mg2,AlMg and Al12Mg17,respectively.The fracture failure of the joints takes place between Mg-Al compound layers and the fracture surfaces exhibit typical brittle failure feature.