Al-Si焊丝对冷金属过渡焊接PBF-LB/M AlSi10Mg合金接头组织与力学性能的影响

Effect of Al-Si Filler Wires on the Microstructure and Mechanical Properties of Cold Metal Transfer Welded AlSi10Mg Alloy Joints Fabricated Using Powder Bed Fusion Laser Beam/Metal

摘要:

采用ER4043（Al-Si5）和ER4047（Al-Si12）2种焊丝对激光粉末床熔融（powder bed fusion laser beam/metal，PBF-LB/M）成形AlSi10Mg合金薄板进行冷金属过渡（cold metal transfer，CMT）对接焊接试验，研究了2种Al-Si焊丝对焊缝成形、气孔特征、微观结构和接头力学性能的影响。结果表明，添加ER4043焊丝可降低焊缝气孔率并减小气孔尺寸，而添加ER4047焊丝则表现出更优异的接头力学性能，其接头的抗拉强度达211.7 MPa，较ER4043焊丝提升了6.7%，且焊缝的平均显微硬度（76.8 HV）较ER4043焊丝焊缝提升了15.5%，表明高Si含量的ER4047焊丝更有利于获得综合性能优异的焊接接头。微观组织分析表明，添加ER4047焊丝接头强度的提升机制主要在于焊缝的固溶强化、细晶强化、织构强化、Si相的析出强化以及共晶Si网的承载效应对于接头强度的贡献。

Abstract:

The cold metal transfer (CMT) butt welding was conducted on AlSi10Mg alloy thin sheets prepared by the powder bed fusion laser beam/metal (PBF-LB/M) technique using two types of filler wires, including ER4043 (Al-Si5) and ER4047 (Al-Si12). The effects of the two wires on weld geometry, porosity, microstructure, and mechanical properties of the welded joints were evaluated. Results indicate that the adding ER4043 wire effectively reduces porosity rate and pore size of the weld metal. In contrast, the ER4047 wire exhibits improved mechanical performance. The ultimate tensile strength of joints welded with ER4047 wire reaches 211.7 MPa, representing a 6.7% increase compared to the 198.4 MPa achieved with ER4043 wire. The average microhardness of the ER4047 weld (76.8 HV) increases by 15.5% compared to that of ER4043 weld. These findings suggest that the higher Si content in ER4047 filler wire is more conducive to achieving superior joint properties. Microstructural analysis attributes this enhancement to a combination of solid solution strengthening, fine grain strengthening, texture strengthening, nanoscale Si precipitation, and the load-bearing contribution of the eutectic Si network.