Estimation of Dislocation Density Using Electron Channelling Contrast Imaging in Ti-Hastelloy-N

In the present study, using electron channelling contrast imaging (ECCI) technique dislocation densities were estimated in Ti-modified Hastelloy-N deformed to a nominal strain of 0.1. These dislocations were imaged using the backscattered electrons signal under controlled two beam diffraction conditions in SEM. To obtain such a condition, the crystallographic orientation of the grain is evaluated from the electron backscattered diffraction (EBSD) patterns. The grain is then oriented to a desired diffracting condition w.r.t electron beam using the tilt and rotation angles of the SEM stage. For this purpose, a software has been developed which helps in manoeuvring the crystal to different diffracting conditions by estimating the permissible tilt and rotation angles of the SEM stage due to its geometry. The dislocation densities obtained from this technique are corroborated with that of TEM.