Digital image correlation studies for microscopic strain distribution and damage in dual phase steels

We have measured the microscopic strain distribution of a dual phase steel at the grain scale, using digital image correlation based on scanning electron microscopy topography images at large strains. The results show how strain is partitioned between the ferritic and martensitic regions. We find that tempering changes the microscopic strain distribution considerably and that this correlates directly with the tensile properties, including the rate of damage accumulation and the consequent ductility of the material. (C) 2007 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.