CAJ | 학술논문

通过在不锈钢表面预涂钎剂层,采用铝硅共晶钎料实现铝合金/不锈钢TIG熔钎焊连接,获得具有熔焊与钎焊双重性质的对接接头,运用OM、SEM、EDS分析接头的微观组织及成分,通过拉伸实验评定接头的力学性能.结果表明:铝母材局部熔化,与液态钎料混合后凝固形成焊缝,焊缝组织主要由α(Al)基体和在晶界析出的Al-Si共晶相组成;不锈钢不发生熔化,液态钎料与不锈钢在界面反应形成不均匀分布的金属间化合物层,最大厚度不超过10 μm,界面上部金属间化合物较厚,呈锯齿状,主要相成分为α(τ5)-Al7.4Fe2Si;界面下部金属间化合物较薄,呈细须状,由α(τ5)-Al7.4Fe2Si+α(Al)混合相构成;接头的平均抗拉强度为90.6 MPa,焊缝/不锈钢界面下部为连接的薄弱环节,成为断裂的起始位置.
통과재불수강표면예도천제층,채용려규공정천료실현려합금/불수강TIG용천한련접,획득구유용한여천한쌍중성질적대접접두,운용OM、SEM、EDS분석접두적미관조직급성분,통과랍신실험평정접두적역학성능.결과표명:려모재국부용화,여액태천료혼합후응고형성한봉,한봉조직주요유α(Al)기체화재정계석출적Al-Si공정상조성;불수강불발생용화,액태천료여불수강재계면반응형성불균균분포적금속간화합물층,최대후도불초과10 μm,계면상부금속간화합물교후,정거치상,주요상성분위α(τ5)-Al7.4Fe2Si;계면하부금속간화합물교박,정세수상,유α(τ5)-Al7.4Fe2Si+α(Al)혼합상구성;접두적평균항랍강도위90.6 MPa,한봉/불수강계면하부위련접적박약배절,성위단렬적기시위치.
Dissimilar metals TIG welding-brazing of aluminum alloy to stainless steel was conducted using Al-Si eutectic wire with precoating special flux layer on the steel surface. The microstructure characteristics of aluminum alloy/stainless steel butt joint were analyzed by OM, SEM and EDS, and the tensile strength of the joint was measured by instron-testing machine. The results show that the aluminum base material is melted and mixed with the liquid filler metal to form the welded seam, which consists of α(Al) matrix and Al-Si eutectic phases in the intergranular. The stainless steel is not melted and reacts with the melted metal to form nonuniform intermetallic compound (IMC) at the welded seam/steel interfacial layer, of which the thickness is less than 10 μm. At the upper part of the layer, the IMC is thick and presents serrated-shape and consists of α(τ5)-Al7.4Fe2Si phase, while at the lower part, the IMC is thinner than the upper part and presents thin whiskered-shape and consists of α(τ5)-Al7.4Fe2Si+α(Al) mixed phases. The average tensile strength of joints is 90.6 MPa and the fracture starts at the lower part of the welded seam/stainless steel interfacial layer, which is the weak bonding zone of the joint.