Dislocation substructure in as-quenched and deformed Ni₃Fe polycrystals

Abstract

Dislocation arrangements and densities in as-quenched and deformed Ni₃Fe polycrystals have been investigated systematically in the plastic strain range from 0.01 to 0.18 using transmission electron microscopy. Dislocation distributions in the as-quenched Ni₃Fe alloy are similar to those of fcc metals of intermediate stacking fault energies. At intermediate strains both dislocation dipoles and elongated loops are formed. A cell structure is developed in the highly strained specimens; the cell size decreases with increasing strain. The average dislocation density increases linearly with plastic strain. A linear relationship between the flow stress and the square root of the average dislocation density is also observed, yielding a relation of τ = 0.96Gb√ρ.