Examination of indention geometry-constitutive behaviour relations with confocal microscopy and finite element modeling

Microhardness measurements have been of general interest in irradiated mate rials testing as a monitor of strength changes, and the geometry of the pil e-up of material around the indentation has been found to be related to the work-hardening behavior. This relationship has been further examined here. Vickers microhardness tests were performed on a variety of metal alloys in cluding low ahoy, high Cr, and austenitic stainless steels and a Nb-Ti allo y. The pile-ups around the identations were quantified using confocal micro scopy techniques. In addition, the indentation process and pile-up geometry was simulated using finite element techniques and the corresponding consti tutive equations for each of the test materials. The results from these met hods have been used to develop an improved understanding and quantification between the pile-up geometry and the constitutive behavior of the test mat erial. (C) 1998 Published by Elsevier Science B.V. All rights reserved.