Effect of crystal orientation on the indentation behaviour of Ni-based single crystal superalloy

The indentation behaviours of Ni-based single crystal (NBSX) superalloy in different crystal orientations are studied by indentation tests and Electron Backscattered Diffraction (EBSD) analysis. The effects of crystal orientations on pile-up modes, dominant slip system distribution and geometrically necessary dislocation (GND) density distribution are revealed by experiments and crystal plasticity finite element (CPFE) simulation. The results and analysis of pyramid and cone indentations show that the pile-up modes produced by different azimuths are significantly different due to the off-plane displacement distribution. The differences of crystallographic slip behaviors under different crystal orientations induce different slip line and indentation symmetry patterns. EBSD observation and CPFE analysis indicate the dependence of GND density distribution on crystal orientations. The results of indentation tests, EBSD observation and CPFE simulation achieve good agreements.