Study of the dislocation structure involved in a nanoindentation test by atomic force microscopy and controlled chemical etching

In this paper, it is shown that combining AFM, chemical etching and controlled polishing, progressively removing thin layers of material, allows a three-dimensional reconstruction of the volume distribution of dislocations about and under nanoindentation imprints. To illustrate the method, results obtained in MgO, a material known for its simple plasticity, have been selected. It is shown, comparing surface deformation and etching pattern, that the entire dislocation distribution associated with small indents can be analysed in terms of individual dislocations, leading to a better understanding of the elementary mechanisms of plasticity associated with the early stages of indents formation in crystalline material. (C) 2002 Acta Materialia Inc. Published by Elsevier Science Ltd. All rights reserved.