In situ Neutron Diffraction Study of Internal Micro‐Stresses Developed by Plastic Elongation in <110> Textured BCC Wires

By in situ neutron diffraction during tensile tests of a strongly <100> textured Nb wire, we have shown the development of internal tensile microstresses of the order of 20 % of the flow stress, acting normal to the longitudinally aligned {110} planes. Such stresses are retained as residual stresses upon unloading. They must be taken into account for preventing splitting failures of high strength BCC wires (e.g., highly drawn tungsten filaments or pearlitic steel wires) that, because of the drawing fabrication process, contain a high density of longitudinally oriented brittle interfaces.