SOME MECHANICAL PROPERTIES OF AUSTENITIC STAIN LESS STEEL SINGLE CRYSTALS

Abstract : Observations on the tensile deformation of single crystals of austenitic stainless steels as a function of composition, orientation and temperature are described and compared with relevant data for other alloys. Crystals free from second phases show sharp yield points followed by Luders' extensions of up to 20%. The critical resolved shear stress is strongly temperature dependent increasing fourfold between 423 K and 77 K. A temperature indepdendent low rate of hardening follows the Luders' extension and is frequently associated with overshoot. Unlike pure metals where profuse cross-slip usually occurs at the end of linear hardening, this stage is terminated either by crossslip or by slip on the conjugate system; the particular node apparently depending upon initial orientation and composition. The presence of ferrite or martensite profound effect upon the magnitude of the yield stress and the shape of the stress-strain curve.