铝合金-不锈钢TIG熔钎焊混合焊丝填充接头组织与性能研究

Microstructure and properties of TIG welding-brazing joints of aluminum-stainless steel with hybrid wires

采用TIG熔钎焊实现了3种组合的混合焊丝铝合金与不锈钢接头的优质连接。采用SEM，EDS对接头进行了微观组织分析，通过拉伸试验和冲击试验评定了接头的力学性能，并分析了接头组织与力学性能之间的关系。结果表明，3种混合焊丝对金属间化合物层的厚度影响不大，均为3～4μm；焊缝组织随着ER2319填充金属的增加，生成的A12cu相增加；ER1100／ER2319混合焊丝的IMC主要为A113，Fe4，而ER2319／ER1100和ER2319／ER2319混合焊丝IMC为θ-A113（Fe，cu）4。采用ER2319／ER1100的混合焊丝时，接头的抗拉强度和冲击吸收能量最高，平均值分别为184MPa和1．83J，比ER1100／ER2319混合焊丝的接头抗拉强度提高了18MPa，而接头冲击吸收能量比ER2319／ER2319的接头提高了近4倍。这主要是因为其IMC为具有高抗裂性的θ-A113（Fe，Cu）4相，且焊缝中含有适量的Al2cu来强化焊缝而又不会明显的降低接头的韧性，因此两者的综合作用结果使接头变现出良好的强韧性。

The high quality joints were obtained by TIG welding- brazing process with three groups of hybrid wires.The microstructure and mechanical properties of the joint were analyzed and tested by the SEM,EDS,tensile test and impact test.The influences of the hybrid wires on microstructures and mechanical properties of the joints were analyzed.The results show the hybrid wires have little effects on the thickness of the intermetallic compounds(IMCs) that the thickness of the IMCs layer was 3-4 μm for each of the three groups.There are more Al_2Cu formed with the increasing filler metal of ER2319 in the weld.The IMCs formed with ER1100/ER2319 hybrid wires was mainly composed by Al_(13)Fe_4.While the IMCs formed with ER2319/ER1100 and ER2319/ER2319 hybrid wires was the θ-Al_(13)(Fe,Cu)_4.The maximum value of tensile strength and impact energy of the joint,184 MPa and 1.83 J respectively,was obtained when the hybrid wires of ER2319/ER1100 was used.The tensile strength of this joint increased by 18 MPa that compared with hybrid wires of ER1100/ER2319,and the impact energy is nearly 4 times than that with hybrid wires of ER2319/ER2319.The main reasons are that the θ- Al_(13)(Fe,Cu)_4 has high cracking resistance and that the appropriate Al_2Cu in the weld has strengthen the weld but not lower the toughness obviously.Hence the joint has the good obdurability due to the both effects.