Small scale testing approach to reveal specific features of slip behavior in BCC metals

Abstract

Plastic behavior of Fe–3%Si was investigated with a novel methodology at microscopic scale and higher stress resolution beyond the existing macroscopic test methods. Activation of single slip system in micropillars under compression provides perfect shear and excludes the lattice rotation. Crystallographic orientation dependency of critical resolved shear stress (CRSS) was observed. Different scenarios regarding activated slip planes are discussed to explain this orientation dependency. Schmid's law approach, which only considers the stress component parallel to the Burgers vector, fails to explain this orientation dependency of CRSS. It is shown that the non-glide stress components should be taken into account in order to precisely define the plasticity in BCC metals.