THE LIQUID-FILM MIGRATION IN A SINTERED FE-CR-C BASE ALLOY

Abstract

In an Fe-5Cr-1Mo-2Cu-0.5P-3C (wt pet) alloy prepared by liquid-phase sintering at 1120 degrees C, the intergranular liquid films migrate during cooling and isothermal heat treatment at temperatures where the solid and liquid phases coexist. The liquid film migration (LFM) occurs extensively even during rapid cooling, apparently because of a large driving force. The migrating liquid films solidify to form network carbides. In the regions swept by the migrating liquid films, the concentrations of the substitutional solute atoms are slightly different from those in the original grains. When cooled rapidly, martensite is abundant in these regions. It is possible that the driving force for LFM in this alloy stems in part from the C concentration change associated with the concentration changes of the slowly diffusing substitutional solute atoms.