Alloying effects on formation of compound layer in the gaseous nitrided Fe-M binary alloys

摘要

In this study, alloying effects on phase structure, thickening kinetics and hardness of the compound layer in gaseous nitrided Fe-M binary alloys were investigated. Pure iron and Fe-lmass%M binary alloys (M = Si, Cr, Al, V, Mn) were nitrided at 843K for various periods. In the pure iron, ε-nitride layer on outer surface of the specimen and y' layer beneath e were formed. The square of the thickness of the overall compound layer is proportional to the nitriding period. The thickness of compound layer is increased by the additions of Si, Mn, V and Cr. Although the compound layer of Fe-lAl alloy is thicker than pure Fe at shorter nitriding time, its growth becomes sluggish resulting in thinner compound layer than pure Fe after prolonged nitriding time. Although hardness of the diffusion zone is increased significantly by the addition of Cr, Al and V due to precipitation of alloy nitrides, alloying effects on the hardness of the compound layer is insignificant.