Lattice rotation field around indentation for identifying slip system interactions coefficients in FCC Nickel single crystal

This study explores the interest of the misorientation angle field surrounding an indent as an observable for identifying plastic parameters in Face-Centered Cubic (FCC) Nickel single crystals using an inverse method. This misorientation angle field, derived from lattice rotations, is directly linked to slip system activity within a crystal plasticity framework. The ten parameters to be identified belong to a Meric–Cailletaud-type crystal plasticity model, governing both slip system interactions and hardening mechanisms. Previous approaches, such as nanoindentation load–displacement curves, often suffer from poor conditioning of the inverse problem associated with identifying the 10 crystal plasticity parameters, while residual topographies typically require multiple crystal orientations to achieve an acceptable conditioning. In contrast, the present work provides a numerical proof of concept, through an identifiability analysis, that a single crystallographic orientation of an FCC Nickel single crystal is sufficient to well-condition the inverse problem, when the three-dimensional misorientation angle is used as the observable.