부산대학교 도서관

The effect of the manganese content (0.5-2.0 wt.%) on the microstructure, mechanical properties and high temperature oxidation resistance of reduced activation ferritic/martensitic (RAFM) steels was studied. The examinations reveal that the microstructure of the steels shows a fully martensite structure. A large number of M23C6 carbides and a small number of Zr(C, N) carbonitrides were detected in the steels. The results of mechanical experiments showed that the strength increases and the toughness decreases with increasing Mn content. The improvement of strength can be ascribed to solution strengthening by Mn and gain size strengthening by refining lath width. After oxidation at 650 °C for 400 h, both MnCr2O4 oxides and Cr2O3 oxides are founded on the surface of the steels. The steel with 1.2 wt.% Mn exhibit the optimum high temperature oxidation resistance, followed by the steel with 0.5 wt.% Mn. The increase of oxidation resistance can be ascribed to the addition of Mn promotes the formation of Mn oxides, which refined the diameter of MnCr2O4 oxides. The decrease of oxidation resistance mainly due to the higher Mn content reduces the critical concentration of Cr to form Cr oxides (Cr2O3), thus promoting the formation of large-sized Cr2O3 oxides.