Scratching the surface: Elastic rotations beneath nanoscratch and nanoindentation tests

TL;DR

This study explores the residual deformation and lattice rotations beneath nanoscratch and nanoindentation tests on copper, combining experimental HR-EBSD mapping with CPFEM simulations to understand deformation mechanisms during tangential sliding.

Contribution

It introduces a combined experimental and modeling approach to analyze lattice rotations in nano-scratching, revealing detailed 3D rotation fields and their evolution from indentation to steady-state scratching.

Findings

CPFEM simulations accurately reproduce experimental rotation fields.

Lattice rotations are reversed as the indenter moves away from initial indentation.

Deformation mechanisms differ between scratching and indentation.

Abstract

In this paper, we investigate the residual deformation field in the vicinity of nano-scratch tests using two orientations of a Berkovich tip on an (001) Cu single crystal. We compare the deformation with that from indentation, in an attempt to understand the mechanisms of deformation in tangential sliding. The lattice rotation fields are mapped experimentally using high-resolution electron backscatter diffraction (HR-EBSD) on cross-sections prepared using focused ion beam (FIB). A physically-based crystal plasticity finite element model (CPFEM) is used to simulate the lattice rotation fields, and provide insight into the 3D rotation field surrounding nano-scratch experiments, as it transitions from an initial static indentation to a steady-state scratch. The CPFEM simulations capture the experimental rotation fields with good fidelity, and show how the rotations about the scratch direction are reversed as the indenter moves away from the initial indentation.