Assessment of Plastic Deformation Induced by Indentation on a Large Grain on Inconel 600 Using Synchrotron Polychromatic X-ray Microdiffraction

A synchrotron-based three-dimensional (3-D) Laue technique called Differential Aperture X-ray microscopy (DAXM) was used to investigate plastic deformation of Inconel 600 induced by indentation. The DAXM technique is capable of probing up to 60 to 100 μm into the Ni alloy, with micron resolution. A conical indenter was used to generate an indent on a large surface grain on Inconel 600. The DAXM Laue images from the uppermost grain exhibited pronounced streaking and splitting of Laue spots, which increased as the grain boundary was approached. Splitting of the Laue patterns correlates with subgrain or dislocation cell formation. A significant amount of dislocation cell formation was found within the 1-μm voxels probed by DAXM. A change in total angle of 8.79 deg was determined for the uppermost grain from the diffraction data from depths 4 to 28 μm, with an average misorientation angle of 2.15 deg between the dislocation cells. The next grain having a different crystallographic orientation continued to rotate in the same direction as the uppermost grain due to the large plastic deformation.