The microstructure of aluminized type 310 stainless steel

The aluminized coating on 310 stainless steel was prepared by pack cementation method and the microstructure of the coating was studied by transmission electron microscopy. The coating consists of a thick outer zone and a thin interfacial zone. The matrix of the outer zone is δ-Fe2Al5 with scattered Cr5Al8 grains. The interfacial zone is made up of two layers; a layer of mixed α-(Cr, Fe) and β-FeAl grains with β-FeAl precipitates in the α-(Cr, Fe) grain, and a β-FeAl layer. A thin layer of polygonized γ phase is present in the γ substrate next to the coating/substrate interface. Dense dislocations are present in the interfacial zone and the substrate near the coating/substrate interface. No crystallographic relationship was found at any of the interfaces between the layers.