SUBSTRUCTURE STRENGTHENING IN FE-V-NI ALLOYS

Models for substructure and dislocation strengthing are examined in deformed and annealed Fe-V-Ni solid solutions. The dislocation substructure depends on the mode of deformation with uniform subgrains produced by swaging and nonuniform dislocation substructures resulting from rolling. The subgrain misorientation and size are the predominant variable influencing the yield strength; the effects of these parameters are consistent with predictions from models based on either dislocation pile-ups or dislocation density. The dislocation density model is considered more plausible in view of the similar strengthening observed in both swaged and rolled materials, despite the differences in dislocation structure. The apparently insignificant contribution to strength by grain boundaries and the absence of dislocation pile-ups in the microstructure add support to this proposal.