LAUSR

The effects of nitrogen on the characteristics and evolutions of M2C eutectic carbides in the Fe-Mo-W-Co-Cr-V-C alloy were investigated in both as-cast and wrought states. Microstructural observation, electrolytic extraction method, and x-ray diffraction analysis were conducted on the specimens. The results showed that, in the case of low nitrogen concentration (w[N]% = 0.006) in the as-cast alloy, lamellar M2C carbides were found to be the dominant precipitate. Nitrogen addition resulted in M2C carbide precipitate as a fibrous structure rather than a lamellar structure. Fibrous M2C were more likely to decompose into fine spherical M6C and V(C,N) during the forging process compared to lamellar M2C. Accordingly, it was suggested that adding nitrogen to Fe-Mo-W-Co-Cr-V-C alloy was required to achieve small dimensions and homogeneous distribution of carbides.