マルテンサイト系耐熱鋼中のM_<23>C_6のオストワルド成長に対するWの影響(相変態・材料組織)

概要

論文の詳細を見る
It is well known that tungsten (W) is the key element for creep strength of the advanced martensitic heat resistant steels developed for main steam pipe in ultra-super critical power plant. W is found to suppress coarsening of M_<23>C_6 type carbide during creep at elevated temperatures, which can never be predicted according to the conventional Ostwald ripening model for a Fe-X-C system in αFe. In this study, therefore, the effect of W on the coarsening of M_<23>C_6 during aging has been analyzed in a detailed experiment and modeled using a modified Ostwald ripening equation for Fe-X_1-X_2-C system. It is found that W substitutes only for Cr in M_<23>C_6 lattice to form [Fe_4(Cr,W)_<19>]C_6. Using the modified Ostwald ripening equation the coarsening of M_<23>C_6 is found to be controlled by the lattice-diffusion of W, resulting in the coarsening rate reduced about one order of magnitude by 1% W addition.
社団法人日本鉄鋼協会の論文
2005-02-01