5A06铝合金棒非真空瞬间液相扩散连接工艺

Non-vacuum transient liquid phase diffusion bonding process for 5A06 aluminum alloy rod

采用成分为Al-7Si-20Cu-3Mg-3Zn-1Ni-1Ga的自制中间层,对5A06铝合金棒进行非真空瞬间液相扩散连接。借助扫描电镜、X射线衍射、电子探针和万能拉伸机等对不同焊接工艺下的接头微观组织形貌与力学性能进行研究,建立微观组织与断口形貌之间的联系,并讨论不同焊接工艺参数对接头连接过程的影响。结果表明,在焊接温度为550℃,保温时间为20 min时,接头的力学性能最佳,平均抗拉强度达到201 MPa,约为母材强度的72%。随着焊接温度的升高,接头会因过高的焊接温度而氧化,同时在焊接压力的作用下,接头因软化而产生裂纹;随着保温时间的增加,焊缝中心形成少量条块状Al-Mg-Cu三元共晶相及少量SiO_(2),部分SiO_(2)之间发生偏聚导致难以焊合,进而在焊缝中产生裂纹,严重影响接头性能。

Non-vacuum transient liquid phase diffusion bonding of 5A06 aluminum alloy rods was carried out by using a self-made interlayer with a composition of Al-7Si-20Cu-3Mg-3Zn-1Ni-1Ga.Microstructure and mechanical properties of the joints under different welding processes were studied by means of scanning electron microscopy,X-ray diffraction,electron probe and universal tensile machine.The relationship between microstructure and fracture morphology was established,and the effects of different welding process parameters on the joint connection process were discussed.The results show that when the welding temperature is 550℃and the holding time is 20 min,the mechanical properties of the joint are the best,with an average tensile strength of 201 MPa,which is about 72%of the strength of the base metal.With the increase of welding temperature,the joint will be oxidized due to excessive welding temperature,and under the action of welding pressure,the joint will crack due to softening.With the increase of holding time,a small amount of block-like Al-Mg-Cu ternary eutectic phase and a small amount of SiO_(2) are formed at the center of the weld,the segregation of some SiO_(2) occurs between them,making it difficult to weld and resulting in the cracks in the weld,seriously affecting the joint performance.