Prediction of bulk tensile behavior of dual phase stainless steels using constituent behavior from micropillar compression experiments

Micropillar compression has become an attractive method to probe local mechanical behavior. While most micropillar compression work has focused on investigating size effects, we can also use this technique to obtain the constitutive behavior of microscopic phases and constituents. In this study, micropillars of ferrite and martensite were fabricated by focused ion beam (FIB) milling of dual phase precipitation hardened powder metallurgy (PM) stainless steels. Compression testing was conducted using a nanoindenter equipped with a flat punch indenter. The stress-strain curves of the individual microconstituents were obtained. Using a rule of mixtures approach in conjunction with porosity corrections, the mechanical properties of ferrite and martensite were combined to predict the tensile behavior of the bulk material, and reasonable agreement was found for the ultimate tensile strength.