Coarsening of MX nitrides in Cr-Mo-N-X(X=V,Nb,Ti) ferritic steels

Abstract

Ferritic steels have been candidate structural materials for first wall and blanket structures of fusion power plant since the late 1970's, when the fast-reactor irradiation showed them to be more swelling resistant than austenitic stainless steels. In this investigation, the coarsening of NIX nitrides during aging was studied for Cr-Mo-N-X(X=V, Nb, Ti) ferritic steels. During the aging, (V, Nb, Ti)nitrides were precipitated out. From TEM observation, particle size distribution was confirmed and size distribution follows a typical log-normal distribution. The coarsening rate of NIX nitrides was correlated with the Oswald ripening equation.