Indentation instrumentée multi-échelles appliquée à l'étude des matériaux massifs métalliques

Abstract

The instrumented indentation test (ITT) is a largely used technique, because it allows to estimate the mechanical properties of materials, as hardness and Young's modulus. This study about multi-scale ITT (from 5 mN to 2 kN) was performed on bulk metallic materials (steel, stainless steel and aluminum) using three instruments: nano, micro and macro indenter, and different kinds of test: standard, CSM and multicycle. We have found that for the estimation of the mechanical properties, it is necessary to consider the correction of the frame compliance and tip defect, for all the scales of measurement and instruments. In these conditions, considering these corrections, the Young's modulus is almost constant among all the range of studied loads (<12%), being an intrinsic property. On the contrary, the hardness decreases while increasing the load, which is typically attributed to the indentation size effect, but also it can be related to the deformation around the imprint, pile-up for the samples of steel and aluminum, and sink-in for the stainless steel.