Interfacial Microstructure and Properties of Steel/Aluminum Powder Additive
YUAN Jiang1,2,3, ZHOU Dian-wu3, CHEN Sheng-qian1,2, SUN Jia-yao1, HOU De-zheng1
1 Zhangjiajie Aviation Industry Vocational Technical College, Zhangjiajie 427000, Hunan, China;
2 Guangdong Institute of Materials and Processing, Guangzhou 510650, China;
3 State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, Hunan University, Changsha 410082, China
Abstract：Based on first-principles density functional theory, the Fe/Al interface model of steel/aluminum laser welding was constructed by layer technique. The Fe/Al interface was studied by metal atom X (X=Sn, Sr, Zr, Ce, La).The results show that Sn, Sr and Ce preferentially displace the Al atoms at the Fe/Al interface, while La and Zr preferentially displace the Fe atoms at the Fe/Al interface. Alloying promotes the transfer of Fe/Al interfacial electrons between different orbits, enhances the ionic bond properties of Fe-Al, improves the Fe/Al interface binding capacity, improves the brittle fracture of Fe/Al interface, and the alloying effect of Sn most notable. On the basis of this, the laser lap welding test of Sn and Zr powder was carried out on 1.4mm thick DC51D+ZF galvanized steel and 1.2mm thick 6016 aluminum alloy specimen. The results show that the addition of powder can promote the flowability of the molten bath and change the composition and microstructure of the joint interface. The tensile strength of the steel/aluminum joint is 327.41MPa and the elongation is 22.93% with the addition of Sn powder, which is obviously improved compared with the addition of Zr powder and without the addition of powder.
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