C. J. Li, H. T. Wang, G. J. Yang, C. X. Li, School of Materials Science and Engineering, Xi'an Jiaotong University, Xi'an, China; W. Y. Li, Northwestern Polytechnical University,, Xi'an, China
Nanostructured FeAl intermetallic compound coating was prepared by cold spraying using a ball-milled Fe-40at%Al alloy powder. The deposit was then annealed at different conditions to transfer the Fe-Al alloy to intermetallic compound. Microstructural evolution of Fe-40Al powder with mechanical alloying and cold sprayed Fe-Al coating with annealing treatment were characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy and x-ray diffraction analysis. The results showed that as-milled Fe-40Al powder has lamellar microstructure, which was continually refined with increasing ball-milling time. It was found that the microstructure of the as-sprayed coating depends significantly on the microstructure of as-milled powder. The annealing treatment at a temperature of above 400oC results in the transformation of Fe-Al alloy to the intermetallic compound. The grain size of the coating depends on annealing condition. Annealing at low temperature results in formation of nanostructured FeAl intermetallic compound. Moreover, the annealing at a high temperature promotes the diffusion between particle boundaries to form a densely bonded coating.
Summary: Nanostructured FeAl intermetallic compound coating was prepared by cold spraying using a ball-milled Fe-40at%Al alloy powder. The deposit was then annealed at different conditions to transfer the Fe-Al alloy to intermetallic compound. Microstructural evolution of Fe-40Al powder with mechanical alloying and cold sprayed Fe-Al coating with annealing treatment were characterized by optical microscopy, scanning electron microscopy, transmission electron microscopy and x-ray diffraction analysis. The results showed that as-milled Fe-40Al powder has lamellar microstructure, which was continually refined with increasing ball-milling time. It was found that the microstructure of the as-sprayed coating depends significantly on the microstructure of as-milled powder. The annealing treatment at a temperature of above 400oC results in the transformation of Fe-Al alloy to the intermetallic compound. The grain size of the coating depends on annealing condition. Annealing at low temperature results in formation of nanostructured FeAl intermetallic compound. Moreover, the annealing at a high temperature promotes the diffusion between particle boundaries to form a densely bonded coating.
