Effect of hydrogenation on deformation behaviour of ferritic-pearlitic steel studied by digital image correlation method

The effect of hydrogenation on room temperature tensile deformation behaviour of ferritic-pearlitic steel was studied. The process of hydrogenation was realised by annealing in flowing hydrogen followed by a fast cooling to room temperature. The room temperature tensile deformation behaviour of hydrogenated and annealed specimens was studied by the digital image correlation (DIC) method. Tensile elongation and reduction of the area were measured on the surface of cylindrical specimens coated with random speckle patterns using stereo CCD camera system. DIC elongation data were related to the data measured by an extensometer touching the specimen gauge section. The data from the DIC method were used for calculations of true stress-true strain tensile curves. Numerical simulations of strain fields within the gauge region of the specimens using finite element method were validated by the experimental data from the DIC method.