Combination of Digital Image Correlation (DIC) and in situ 3D-mu-CT in the analysis of the relationship between strains and porosity under creep loading

In situ 3D mu-XCT allows the time and space resolved measurement and analysis of material damage in the component volume, whereas the Digital Image Correlation (DIC) is a 2D method for the analysis of deformation measured on the surfaces of components. In situ 3D mu-XCT measurements were performed on cylindrical specimen made of SiC particle reinforced titanium MMC (MMC: Metal Matrix Composite) (15 % SiC particles) during creep load. The formation and evolution of voids were subsequently analyzed. Due to the rotationally symmetric sample geometry, the analysis of the deformation in the interior of the material by DIC using 2D slices is possible and evident. The dot pattern required to calculate the strain using DIC (speckle pattern) is provided by the intrinsic particle reinforcement of the MMCs. Temporally and locally changing and time-variant strain fields in both the tensile as well as the compressive range could be detected correlating with void formation and development area.