Effect of Temperature on Microstructure and Formability of Al-10 mass% Si Coatings
Jie ZHANG1,2,She-ming JIANG1,Qi-fu ZHANG1,Chang-sheng LIU2
1. National Engineering Laboratory Advanced Coating Technology for Metals, Central Iron and Steel Research Institute, Beijing 100081, China 2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, Liaoning, China
Effect of Temperature on Microstructure and Formability of Al-10 mass% Si Coatings
Jie ZHANG1,2,She-ming JIANG1,Qi-fu ZHANG1,Chang-sheng LIU2
1. National Engineering Laboratory Advanced Coating Technology for Metals, Central Iron and Steel Research Institute, Beijing 100081, China 2. School of Materials and Metallurgy, Northeastern University, Shenyang 110004, Liaoning, China
ժҪ The type-1 aluminized (Al-10 mass% Si) coating on hot stamped steel is used in commercial applications. The effect of temperature on microstructure and formability of the Al-10 mass% Si coating was investigated. Hot-dip aluminized 22MnB5 steel was heated at 870, 900, 930, and 1050 �� for 5 min. After heat treatment at different temperatures, the microstructure of Al-10 mass% Si was characterized by field-emission scanning electron microscopy and energy-dispersive spectroscopy. The results show that when the Al-10 mass% Si coating was heated at 870 �� for 5 min, three types of intermetallic phases were formed: two ternary Fe-Si-Al phases (Fe2SiAl7+Fe2Si2Al5 and Fe2SiAl2+Fe2Si2Al5) and one binary Fe-Al phase (FeAl3). The phases in the coating became Fe2SiAl2+Fe2Si2Al5 and FeAl3, the binary Fe-Al phase near the interface became Fe2Al5 and the Si-rich layers were decreased with the increase of heating temperature. When the heat treatment was 1050 �� for 5 min, the Si-rich layer disappeared, the coating consisted of FeAl and Fe3Al, and the Kirkendall voids were formed. When the heating temperature was increased through 870, 900, and 930 ��, the coating hardness was reduced and cracks were formed in the coating after hot stamping. The formability of the coating with temperature change was confirmed by a hot stamping test. When heated at 1050 ��, the coating was formable but continuous Kirkendall voids were observed.
Abstract��The type-1 aluminized (Al-10 mass% Si) coating on hot stamped steel is used in commercial applications. The effect of temperature on microstructure and formability of the Al-10 mass% Si coating was investigated. Hot-dip aluminized 22MnB5 steel was heated at 870, 900, 930, and 1050 �� for 5 min. After heat treatment at different temperatures, the microstructure of Al-10 mass% Si was characterized by field-emission scanning electron microscopy and energy-dispersive spectroscopy. The results show that when the Al-10 mass% Si coating was heated at 870 �� for 5 min, three types of intermetallic phases were formed: two ternary Fe-Si-Al phases (Fe2SiAl7+Fe2Si2Al5 and Fe2SiAl2+Fe2Si2Al5) and one binary Fe-Al phase (FeAl3). The phases in the coating became Fe2SiAl2+Fe2Si2Al5 and FeAl3, the binary Fe-Al phase near the interface became Fe2Al5 and the Si-rich layers were decreased with the increase of heating temperature. When the heat treatment was 1050 �� for 5 min, the Si-rich layer disappeared, the coating consisted of FeAl and Fe3Al, and the Kirkendall voids were formed. When the heating temperature was increased through 870, 900, and 930 ��, the coating hardness was reduced and cracks were formed in the coating after hot stamping. The formability of the coating with temperature change was confirmed by a hot stamping test. When heated at 1050 ��, the coating was formable but continuous Kirkendall voids were observed.
Jie ZHANG,,She-ming JIANG,Qi-fu ZHANG,Chang-sheng LIU. Effect of Temperature on Microstructure and Formability of Al-10 mass% Si Coatings[J]. �й������ڿ���, 2016, 23(3): 270-275.
Jie ZHANG,,She-ming JIANG,Qi-fu ZHANG,Chang-sheng LIU. Effect of Temperature on Microstructure and Formability of Al-10 mass% Si Coatings. Chinese Journal of Iron and Steel, 2016, 23(3): 270-275.
2016, Vol. 23 
