Ductility assessment of a 17-4PH steel through simple multiaxial tests

The present work summarizes the results of an experimental campaign aimed at assessing the ductility of a wrought 17-4PH steel alloy. A simple specimen reproducing multiaxial stress states through a universal testing machine is selected. A Finite Element Model (FEM) for each test is setup to extract the local values of stress and strain in the most critical point on the onset of failure. A Digital Image Correlation (DIC) technique is employed to assess the strain field estimated via FEM. The collected data are used to analyse the material ductility, calculating the triaxiality and deviatoric parameter at the fracture strain. The proposed tests fall in the range of low triaxialities, which are less investigated in the literature. The results obtained are compared with the prediction of a damage model, previously calibrated on the material through more conventional tests. The prediction accuracy of the damage model was fully confirmed by the outcome of the new tests. Eventually, the possibility of replacing some of the conventional tests used for calibration with the proposed specimen is explored.