Volume 35, Issue 3 (May 2007)
An Evaluation of Stress-Strain Property Prediction by Automated Ball Indentation (ABI) testing
Automated ball-indentation tests were performed on a duplex stainless steel (2205) and on a high-strength Al-Cu alloy (2014-T651) using a tungsten carbide (TC) spherical ball indenter to derive the materials' stress-strain parameters, which were validated with standard tensile specimen data. Test method and data analysis procedures, as proposed by Haggag et al. in a previous research publication, were followed. During analysis, we observed some interesting details, such as the existence of a linear relationship between the maximum applied compressive force and the plastic depth of penetration for a given material, a relationship between force and plastic diameter of indentation, and a unique relationship between plastic diameter of indentation and plastic depth of indentation, which is independent of the material being evaluated. The correlation between ABI derived stress-strain data and tensile stress-strain data was reasonable for duplex stainless steel, whereas the correlation was not good in the case of Al-Cu alloy 2014-T651. This work suggests the need to improve the formulations, taking into account the properties of indenter and indenting material, as well as the need to account for events such as sink-in and pile-up that take place during indentation.