激光填丝焊与TIG焊增材修复2A50铝合金:组织及性能对比

Laser Wire-Feed Welding versus TIG Welding for Addtitive Repair of 2A50 Aluminum Alloy:Comparsion of Microstructure and Mechanical Property Restoration Effects

  • 摘要: 某型飞机2A50铝合金部件表面出现损伤需局部精密修复,针对2A50铝合金焊接中易出现气孔、热裂纹倾向等特点,对样件使用ER4043焊丝分别进行TIG焊与300W小功率脉冲激光填丝焊增材修复试验,旨在研究最佳的修复方式。对两种修复方式焊后修复区、熔合区微观组织、显微硬度及力学性能进行研究。研究发现两种修复方式修复区均有共晶硅析出,TIG焊修复修复区有大量粗大针状共晶硅析出,存在于α-Al的枝晶间。激光焊修复共晶硅为细小的颗粒状或纤维状。激光焊修复区的晶粒尺寸要明显小于TIG焊修复区晶粒。TIG焊与激光焊修复后样件平均抗拉强度分别达到318.5MPa、378.5MPa,断裂延伸率分别达到8.1%、14%。因此在激光焊增材修复方式下,由于细晶强化、析出强化的作用,修复区综合性能更加符合使用标准。

     

    Abstract: Local precision repair is required for the surface damage of 2A50 aluminum alloy components in a certain type of aircraft. Given the characteristics of 2A50 aluminum alloy such as susceptibility to porosity and hot cracking tendency during welding, additive repair tests using ER4043 welding wire were conducted on the samples via TIG welding and 300W low-power pulsed laser wire-filled welding respectively, aiming to explore the optimal repair method. The microstructures, microhardness, and mechanical properties of the repaired zones and fusion zones after welding by the two repair methods were studied.The study found that eutectic silicon precipitated in the repaired zones of both methods. Specifically, a large number of coarse acicular eutectic silicon precipitated in the repaired zone of TIG welding, which was distributed between the dendrites of α-Al. In contrast, the eutectic silicon in the laser-welded repaired zone appeared as fine particles or fibers. Moreover, the grain size in the laser-welded repaired zone was significantly smaller than that in the TIG-welded repaired zone.After repair, the average tensile strengths of the samples repaired by TIG welding and laser welding reached 318.5MPa and 378.5MPa respectively, with fracture elongations of 8.1% and 14% respectively. Therefore, under the laser welding additive repair method, due to the effects of grain refinement strengthening and precipitation strengthening, the comprehensive performance of the repaired zone is more in line with the service standards.

     

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