Influence of normal stress on yielding behaviour in Fe -3 ·2% Si alloy single crystals

Abstract

Specimens of Fe-3·2 wt% Si alloy single crystals of various orientations, both with 18 ppm C and decarburized, have been deformed in compression ($\dot \varepsilon$ ∼ 10⁻⁴ s⁻¹) at different temperatures between 125 K and 293 K. It has been found that the magnitude of CRSS, the choice of the slip planes and the shape of the stress-strain curves depend on the angle between the compression axis and the Burgers vector (angleξ). The stress normal to the maximum resolved shear stress plane is strongly altered on changing the angleξ. The discussion of the obtained experimental results seems to indicate that the normal stress influences the structure of screw dislocation core and subsequently the dislocation mobility.