摘要
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10μm,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90.6MPa,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。
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 a（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 10μm. 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 a（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.
出处
《中国有色金属学报》
EI
CAS
CSCD
北大核心
2009年第7期1209-1215,共7页
The Chinese Journal of Nonferrous Metals
基金
国家自然科学基金资助项目(50874033)
关键词
异种金属
钨极氩弧熔钎焊
预涂钎剂层
界面反应层
力学性能
dissimilar metal
TIG welding-brazing
precoating flux layer
interfacial layer
mechanical property
