Localization of plastic strain in Alloy 718 using Digital Image Correlation
Résumé
High Resolution-Digital Image Correlation (HR-DIC) is a powerful tool to assess quantitative kinematic fields across length scales. Recently, HR-DIC was used to identify slip activity at the microstructure scale in different single- or poly-crystalline materials under tensile loading. Identification of slip systems was possible using micrographs from either scanning electron microscopes (SEM) or laser scanning confocal microscopes (LSCM). SEM micrographs provide a high spatial resolution and scanning repeatability while LSCM micrographs provide out-of-plane measurements. Both imaging techniques are therefore complementary to identify crystallographic slip activity at the sub-grain scale.
In the present work, HR-DIC paired with ex-situ LSCM observations was used in order to identify strain localization and subsequently slip activity in the Alloy 718 under tensile loading at room temperature. Tensile specimens were subjected to a two-step tensile test, interrupted at 0.1% and 0.4% plastic strain. Full field inplane kinematics fields and height measurements were assessed using the DisOpticalFlow OpenCV library.