Locating Cracks in 1050 Aluminium Alloy by Digital Image Correlation

Abstract

In this paper deformation of commercial 1050 grade aluminum alloy is studied by digital image correlation (DIC) technique using open-source software, Ncorr. For this purpose, samples of aluminum alloy were subjected to uniaxial deformation under a scanning electron microscope (SEM) till the initiation of crack. Intermittently images were captured during deformation and by using DIC technique, variations in the microstructure of the deformed samples were identified in terms of displacement. Using these displacements, normal strains Exx, Eyy, and Exy shear strain were estimated to subpixel accuracy. By superimposing the region of crack and distribution of strains in the microstructures, it was possible to show that near the crack, strains not only attain high values but also show large fluctuations. Various aspects relating to the nature of strain distribution are discussed in the paper.