MIG焊叠加对6A01-T5铝合金FSW焊接头组织及性能的影响

研究了MIG焊叠加对6A01-T5铝合金FSW焊接头组织及性能的影响. 结果表明, MIG/FSW叠加焊缝熔合良好，叠加位置未出现气孔等缺陷，FSW焊核区及热影响区组织发生粗化，叠加位置附近微观组织出现明显改变；叠加区域硬度明显降低，尤其是FSW焊缝热力影响区和热影响区. FSW、中心叠加、前进侧热力影响区叠加和后退侧热力影响区叠加MIG焊接头的抗拉强度分别为219.8, 188.0, 195.4和191.4 MPa，MIG焊叠加降低了接头的抗拉强度，断口均表现韧性断裂特征；FSW焊接头及带有MIG叠加焊缝余高的三种接头中值疲劳强度分别为76.7, 65.0, 67.5和65.0 MPa，MIG焊叠加也使FSW接头的疲劳性能有所下降.

Effects of MIG welding superposition on microstructure and property of 6A01-T5 FSW joint

Effects of MIG welding superposition on microstructure and property of 6A01-T5 FSW joint was researched in this work. The results indicated that the MIG/FSW joints formed well without porosity defects near the superposition. The microstructure of the FSW weld nugget and heat affected zone became coarse and which near the superposition was changed obviously. The hardness value of the superposition was reduced significantly, especially for FSW thermo-mechanically affected zone and heat affected zone. The tensile strengths of the FSW joint, MIG superposition on the FSW weld center, MIG superposition on the FSW advancing side thermo-mechanically affected zone, and MIG superposition on the FSW retreating side thermo-mechanically affected zone were 219.8 MPa, 188.0 MPa, 195.4 MPa and 191.4 MPa, respectively. MIG superposition reduced the FSW joint tensile strength, and the fracture appearance of all joints belonged to ductile fracture. The median fatigue strengths of above the FSW joint and three joints with MIG weld reinforcement were 76.7 MPa, 65.0 MPa, 67.5 MPa and 65.0 MPa respectively. The MIG superposition was also reduced the fatigue properties of the FSW joints.