Microstructure and Oxidation Resistance of Fe–Cr–Si Alloys
摘要
In the present study, Fe–Cr–Si alloys were prepared using the vacuum arc melting technique, and their microstructure, mechanical properties, and high-temperature oxidation resistance at 900°C were investigated. The results show that the Fe–Cr–Si alloys exhibit a homogeneous microstructure, demonstrating high hardness and fracture toughness. At 900°C, the Fe–Cr–Si alloys demonstrate superior high-temperature oxidation resistance compared to 0Cr18Ni9 stainless steel, exhibiting lower oxidation weight gain and oxidation rate. The oxidation kinetics curve of the alloys follows a parabolic law. The primary oxidation products of the 75Fe–25Si alloy are SiO2 and Fe2O3. Its oxide scale exhibits partial spallation due to large thermal expansion coefficient mismatch between the oxide scale and the substrate, which leads to crack formation and shear fracture at defects. The introduction of Cr elements can enhance the oxidation resistance of the alloys due to the formation of a more stable Cr2O3–FeSiO3–FeCr2O4 composite oxide film on the surface.