Abstract

Nanoindentation is a well-stablished experiment to study the mechanical properties of materials at the small length scales of micro and nano. Unlike the conventional indentation experiments, the nanoindentation response of the material depends on the corresponding length scales, such as indentation depth, which is commonly termed the size effect. In the current work, first, the conventional experimental observations and theoretical models of the size effect during nanoindentation are reviewed in the case of crystalline metals, which are the focus of the current work. Next, the recent advancements in the visualization of the dislocation structure during the nanoindentation experiment is discussed, and the observed underlying mechanisms of the size effect are addressed. Finally, the recent computer simulations using molecular dynamics are reviewed as a powerful tool to investigate the nanoindentation experiment and its governing mechanisms of the size effect.

Highlights

  • The size effect in material science is the variation of material properties as the sample characteristic length changes

  • The indentation size effects crystalline metals including the variation of hardness versus the indentation depth for geometrically in crystalline metals including the variation of hardness versus the indentation depth for geometrically self-similar indenter tips and variation of hardness versus the indenter radius for spherical indenters self-similar indenter tips and variation of hardness versus the indenter radius for spherical indenters are well documented and have been observed by many researchers

  • The size effects have been successfully captured using the concept of geometrically necessary dislocations (GNDs)

Read more

Summary

Introduction

The size effect in material science is the variation of material properties as the sample characteristic length changes. In the case of crystalline metals, the size effect is governed by the dislocation-based mechanisms. The common size effect is the increase in hardness by decreasing the indentation depth. The most accurate method to model the nanoindentation experiment and investigate the underlying physics of the indentation size effect is to model the sample as a cluster of atoms using MD simulation. The focus is on the nanoindentation size effect in crystalline metals, in which the deformation mechanisms are governed by the nucleation and evolution of the dislocation network. The size effect trend in which the hardness increases as the indentation depth decreases is considered in the current review. The aim of this study is to address recent advancements in experiments and atomistic simulation to capture the underlying mechanisms of the size effect during nanoindentation. The details and methodology of atomistic simulations, are beyond the scope of the current work

Classical Experimental Observations and Theoretical Models
Indentation
Interaction of Size Effects during Nanoindentation and Grain Size Effects
The schematic of the interaction betweenthe the GNDs
Recent Experimental Observations and Theoretical Models
Atomistic Simulation of Nanoindentation
Summary and Conclusions
Full Text
Published version (Free)

Talk to us

Join us for a 30 min session where you can share your feedback and ask us any queries you have

Schedule a call