Microstructure, Mechanical Properties and Fracture Behavior of Magnesium/Steel Bimetal Using Compound Casting Assisted with Hot-Dip Aluminizing

• Published in: Metals and materials international Vol. 27; no. 8; pp. 2977 - 2988
• Main Authors: Jiang, Wenming, Jiang, Haixiao, Li, Guangyu, Guan, Feng, Zhu, Junwen, Fan, Zitian
• Format: Journal Article
• Language: English
• Published: Seoul The Korean Institute of Metals and Materials 01.08.2021; Springer Nature B.V; 대한금속·재료학회
• Subjects: Bimetals; Characterization and Evaluation of Materials; Chemistry and Materials Science; Engineering Thermodynamics; Graphical representations; Heat and Mass Transfer; Hot dip aluminizing; Intermetallic compounds; Iron and steel making; Machines; Magnesium; Magnetic Materials; Magnetism; Manufacturing; Materials Science; Mechanical properties; Metallic Materials; Metallurgy; Microstructure; Nanohardness; Processes; Shear strength; Solid Mechanics; Substrates; Thickness; 재료공학; Aluminizing; Compound casting; Magnesium; Steel; Interface; Bimetal
• ISSN: 1598-9623; 2005-4149
• DOI: 10.1007/s12540-019-00606-7

In this work, microstructure, mechanical properties and fracture behavior of the magnesium/steel bimetal using compound casting assisted with hot-dip aluminizing were investigated, and the interface bonding mechanism of the magnesium/steel bimetal were also analyzed. The results indicate that the magnesium/steel bimetal obtained without hot-dip aluminizing had larger gaps through the whole interface without reaction layers between magnesium and steel, leading to a poor mechanical bonding. After the steel substrate was hot-dip aluminized, an intermetallic layer along with an Al topcoat layer were formed on the surface of the steel substrate, and the intermetallic layer was constituted by Fe 2 Al 5 , τ 10 -Al 9 Fe 4 Si 3 , FeAl 3 and τ 6 -Al 4.5 FeSi phases. In the case of the magnesium/steel bimetal obtained with hot-dip aluminizing, a compact and uniform interface layer with an average thickness of about 17 μm that consisted of Fe 2 Al 5 , τ 10 -Al 9 Fe 4 Si 3 , FeAl 3 and Al 12 Mg 17 intermetallic compounds was formed between the magnesium and the steel, obtaining a superior metallurgical bonding. The interface layer had much higher nano-hardnesses compared to the magnesium and steel matrixes, and its average nano-hardness was up to 11.1 GPa, while there were respectively 1.1 and 4.2 GPa for the magnesium and steel matrixes. The shear strength of the magnesium/steel bimetal with hot-dip aluminizing reached to 23.3 MPa, which increased by 8.59 times than that of the composites without hot-dip aluminizing. The fracture of the magnesium/steel bimetal with hot-dip aluminizing represented a brittle fracture nature, initiating from the interface layer. Graphic Abstract