Microstructural Evolution and Anisotropic Mechanical Properties of 316L Stainless Steel Induced by Tensile Straining

Microstructures and mechanical properties of tensile-strained 316L stainless steel are investigated using x-ray diffraction, electron backscatter diffraction, transmission electron microscopy, and mechanical tests to elucidate the underlying mechanisms for the evolved anisotropic mechanical properties. The straining facilitates the formation of dislocations, twins and martensite, and the yield strength increases with the strain while the elongation and the impact toughness exhibit the opposite trend. Under the same strain, the yield strength tested at angles of 0°, 45° and 90° and the impact toughness tested at angles of 0° and 90° to the straining direction are successively decreased, and this anisotropy will enhance with the strain extent. The yield strength is increased due to the higher dislocation and second-phase (martensite) hardening. The microstructure, the yield strength and the impact toughness are correlated, proving the linkage between the orientation dependence of the mechanical properties.