Processing and characterization of graded metal/intermetallic materials: The example of Fe/FeAl intermetallics

Nanocomposite Fe-Al Intermetallic Coating Obtained by Gas Detonation Spraying of Milled Self-Decomposing Powder

“…It also confirms that the nanocrystalline B2 FeAl superlattice was inherited from the as-milled selfdecomposing powder under the experimental conditions of the GDS process. The preferential location for Fe 3 Al phase formation is the nearest boundary to the oxide phases formed in situ under the GDS conditions, which are characterized by Al depletion to the range of 26-33 at.% (Fig. 8c).…”

“…8c). The nanocrystalline lamellar subgrains were identified as Fe 3 Al phase with a significant density of dislocations, undoubtedly originating from the internal compressive stresses caused by the high impulse pressure and high kinetic energy of the high-velocity powder particles during the GDS process as well as the presence of dispersive thin films of hard Al 2 O 3 oxides. As a result of the high temperature of the GDS metallization stream as well as the very high kinetic energy of the powder particles during their collision with the substrate, some powder particles are partially melted and aluminum reacts with oxygen to form oxides, mainly in the form of alumina thin films that undergo amorphization (Fig.…”

“…11). Since the layered structure of the coating consists of grains with varying degree of grayness as observed by a scanning TEM (STEM) detector, the qualitative analysis based on mappings helped to determine that Fe was present in very bright areas, being identified as Fe 3 Al, and in less bright ones containing FeAl phase with 38-42 at.% Fe. Aluminum identified as Al 2 O 3 was found in dark areas and grey grains, in which the occurrence of the FeAl phase with increased Al content was confirmed.…”

“…Iron aluminide-based intermetallic alloys are attractive materials for industrial applications at medium to high temperatures due to their unique properties, which are generally ascribed to their long-range ordered (LRO) crystal structures (Ref [1][2][3][4]. Consequently, they exhibit relatively good mechanical properties, relatively low density (5.56 g/cm 3 for the FeAl phase), excellent corrosion resistance (as a result of their ability to create a highly protective Al 2 O 3 layer), and low cost.…”

“…Consequently, they exhibit relatively good mechanical properties, relatively low density (5.56 g/cm 3 for the FeAl phase), excellent corrosion resistance (as a result of their ability to create a highly protective Al 2 O 3 layer), and low cost. It is found that the B2 ordered FeAl phase exists in the range from approximately 26 to 52 at.% Al depending on the temperature (Ref 4).…”