Portevin-Le Chatelier type plastic instabilities in depth sensing macro-indentation

Depth-sensing indentation at constant loading rate was applied to investigate the Portevin-Le Chatelier effect. Comparison of the different testing methods was achieved using representative strain and stress quantities. The depth of the dynamic strain ageing shows a good coincidence for Vickers and conical indentations, and for the large strain region of the tension tests. Tests with cylindrical indenters and tension experiments show a transient and a stationary behaviour for small and for large strains, respectively. The transient part can be interpreted by taking into account the free-flight time of dislocations in the Kubin-Estrin model. (C) 2002 Elsevier Science B.V. All rights reserved.