Strain mapping with high spatial resolution across a wide observation range by digital image correlation on plastic replicas

In this study, a one-step replica method was applied at 0, 3, and 7% plastic strains in pearlitic steel. A microstructural digital image correlation was then performed on acetyl cellulose plastic replica surface images to obtain high spatial resolution strain maps across a wide observation range. In order to validate the digital image correlation on the replica, digital image correlation was also conducted on the chemically etched sample surface. Although the digital image correlation results were affected by replica shrinkage, its effect could be corrected by a simple experimental equation relating the shrinkage ratio dependence on the solvent immersion time. Reproducible strain maps were obtained for the plastic replica for any macroscopic strain, strain components, or degree of microscopic strain localization.