Strain gradient plasticity modeling of nanoindentation of additively manufactured stainless steel

Nanoindentation can be used to probe the mechanical behavior of additively manufactured materials, but requires a fundamental understanding of inhomogeneous deformation and size effects at the various length scales involved. Here we perform gradient plasticity finite element (GPFE) simulations of nanoindentation of additively manufactured stainless steel layers on stainless steel baseplates. The GPFE simulation results, when compared with their experimental nanoindentation counterparts, capture the size dependence of indentation hardness arising from strong plastic strain gradients developed at small indentation depths. Furthermore, they address the strengthening effects due to the interplay of several characteristic length scales involved, including the indentation depth, the grain size, and the size of printing-induced dislocation cells. This work demonstrates that GPFE simulations can be effectively applied for quantitative evaluation and mechanistic understanding of the nanoindentation behavior of additively manufactured materials. (C) 2021 Elsevier Ltd. All rights reserved.

Automated summary

This study investigates the nanoindentation behavior of additively manufactured stainless steel materials through gradient plasticity finite element simulations, revealing size dependence of indentation hardness and strengthening effects due to the interplay of characteristic length scales.