Investigation of the thermal deformation behavior exhibited by oxidation products in Fe-Si alloys

The thermal deformation behavior of oxidation products from Fe-Si alloys with varying Si contents was systematically investigated using a thermal simulation testing machine during compressive deformation at temperatures ranging from 800 to 1100 ℃. The results indicate that FeO exhibits excellent plastic deformation ability and is the primary component undergoing deformation during the thermal process. The plasticity of the oxide product improves with higher deformation temperature, as does the coordination between the oxide product and matrix, and interface straightness. However, an increase in Si content leads to a decrease in FeO content within the oxide product, resulting in reduced overall plastic deformation ability and reduced deformation coordination of oxidation products with the substrate. At the interface, Fe 2 SiO 4 forms a spinel solid solution composed of Fe 2 SiO 4 with FeO and SiO 2 that possesses a certain plastic deformation ability due to its FeO content. Moreover, the rise in Si content leads to an increased concentration of point defects in FeO near the interface side of the matrix, thereby facilitating dislocation climbing of FeO and resulting in a steady-state increase in plastic deformation. Thus the increase in the concentration of cationic defects in FeO due to the elevated Si content and the generation of Fe 2 SiO 4 solid solution at the interface between the oxidation products and the substrate are the main reasons for the improvement in the flatness of the interface between the oxidation products and the substrate.