Plane strain compression of silicon-iron single crystals

Abstract

Six different orientations of Fe-3 wt% Si single crystals have been deformed in plane strain compression (using a channel die) up to true strains of 0.5. The finite strain behaviours, i.e. the shape changes, lattice rotations and stress-strain curves, are compared with the predictions of the generalized Taylor analysis of partially constrained crystal deformation. The influence of the relative critical resolved shear stresses on the {110} and {112} 〈111〉 glide systems has been systematically examined. It is shown that for most crystals under multiple slip conditions the shape changes and lattice rotations are consistent with the hypothesis of glide on {112} being somewhat easier than on {110}. Comparison with previous work on b.c.c. crystals undergoing large strains leads to the suggestion that: (i) under conditions of single or colinear slip, glide on {110} is easier than on {112}; (ii) under conditions of intersecting 〈111〉 slip directions, glide on {112} is easier than on {110}. For silicon-iron, the critical resolved shear stresses on the {112} 〈111〉 systems, relative to those on the {110}〈111〉 systems are found to be 0.93 and 0.96 for the twinning and anti-twinning senses, respectively.