顯微組織與力學(xué)性能
(1. 北京科技大學(xué) 材料科學(xué)與工程學(xué)院，北京 100083；
2. 廣州市特種承壓設(shè)備檢測研究院，廣州 510100)
摘 要: 采用電弧加熱鍍鋅鋼板，通過熱傳導(dǎo)使鋁合金熔化，形成兩個互不接觸的熔池，實現(xiàn)鋼/鋁異種金屬搭接熔釬焊；利用掃描電鏡(SEM)與能譜(EDS)對連接界面的微觀組織進行觀察與分析。結(jié)果表明：在連接界面形成兩種金屬間化合物，一種為接近鋁合金母材呈針狀或絮狀的FeAl3，另一種為接近鋼呈舌狀或條狀的Fe2Al5；反應(yīng)層FeAl3的厚度在連接界面上的分布大致均勻；而反應(yīng)層Fe2Al5的厚度從焊縫中心向兩側(cè)逐漸變薄；隨著焊接線能量的升高，接頭的承載能力呈先增大而后減小的趨勢，最高承載能力可達177.2 N/mm，為鋁合金母材強度的84%。
關(guān)鍵字: TIG熔釬焊；鋼/鋁異種金屬；金屬間化合物；原子擴散
（1. School of Material Science an Engineering, University of Science and Technology Beijing, Beijing 100083, China;
2. Guangzhou Special Equipment Inspection and Research Institute, Guangzhou 510100, China）
Abstract:In order to achieve overlap tungsten inert gas (TIG) welding-brazing of galvanized steel/aluminum dissimilar metals, the galvanized steel was heated by TIG arc, which melted the aluminum through heat conduction, and then two isolated weld pools were formed. The interfacial microstructures of the joints are observed by a scanning electron microscope (SEM) and a energy dispersive spectrometer (EDS). The results indicate that two intermetallic compounds form along the interface. One is FeAl3, needle or floccule-like, close to the aluminum alloy base metal. The other is Fe2Al5, tongue or strip-liked, close to the steel. The thickness of the FeAl3 compound layer has little difference along the interface, but the thickness of Fe2Al5 compound layer gradually decreases from the weld center to both sides. With the increase of the welding heat input, the load ability of the joints increases first and then decreases, the highest value reaches 177.2 N/mm, which is 84% of that of the Al alloy base metal.
Key words: TIG welding-brazing; steel/aluminum dissimilar metal; intermetallic compounds; atom diffusion
