包覆钎料铝-钢螺柱焊接头组织及性能

采用包覆钎料感应加热方法,以AlSi钎料作为焊缝填充金属,对Q235钢螺柱和6061铝合金进行钎焊.利用光学显微镜、扫描电镜、能谱分析等表征方法,对接头的组织、成分和相组成等进行了分析.结果表明,AlSi钎料与铝母材反应充分,Si元素扩散至铝母材形成针叶状的共晶组织,焊缝近钢侧生成一条狭窄连续的Fe-Al金属间化合物,并沿垂直于铝基体的方向生成出胞状晶,金属间化合物层由Fe2Al5和FeAl3的混合相组织组成.力学性能测试表明,接头的抗剪强度最大为65 MPa,近钢侧金属间化合物的显微硬度值较高,接头断裂在金属间化合物区域,属于延性断裂.

Microstructure characteristics and properties of steel stud to aluminum alloy made by covering filler metal brazing

Q235 steel stud and 6061 aluminum alloy with AlSi as filler metal were joined by using high-frequency induction brazing.Microstructure,composition and phase composition of the welded joint were characterized by optical microscopy,SEM,EDAX EDS diffraction analysis.The results showed that AlSi filler completely reacted to 6061 aluminum base metal,needle-like eutectic was formed with the diffusion of Si to aluminum base metal;continuous Fe-Al intermetallic compounds which should be composed of Fe2Al5 and FeAl3 generated near the steel side in the brazing seam,and some cellular crystal generated along the direction perpendicular to the Al base metal.Mechanical properties tests showed that the shear strength of welding joint was up to 65 MPa,fracture occurred in the Fe-Al intermetallic compounds where the microhardness was high.Fracture properties belonged to ductile fracture.