Molecular Dynamics Simulation of Nanoscale Abrasive Wear of Polycrystalline Silicon

Pengzhe Zhu,Rui Li,Hanyu Gong

doi:10.3390/cryst8120463

Abstract

In this work, molecular dynamics simulations of the nanoscratching of polycrystalline and singlecrystalline silicon substrates using a single-crystal diamond tool are conducted to investigate the grain size effect on the nanoscale wear process of polycrystalline silicon. We find that for a constant indentation depth, both the average normal force and friction force are much larger for single-crystalline silicon compared to polycrystalline silicon. It is also found that, for the polycrystalline substrates, both the average normal force and friction force increase with increasing grain size. However, the friction coefficient decreases with increasing grain size, and is the smallest for single-crystalline silicon. We also find that the quantity of wear atoms increases nonlinearly with the average normal load, inconsistent with Archard’s law. The quantity of wear atoms is smaller for polycrystalline substrates with a larger average grain size. The grain size effect in the nanoscale wear can be attributed to the fact that grain boundaries contribute to the plastic deformation of polycrystalline silicon.

Highlights

Silicon has been the material most commonly used in microelectromechanical systems (MEMS).high wear has been one of the major barriers to the development and commercialization of silicon-based MEMS [1,2,3]
molecular dynamics (MD) simulations of the nanoscratching of polycrystalline and single-crystalline silicon substrates using a single-crystal diamond tool were performed to investigate the effect of grain size on the nanoscale wear process of polycrystalline silicon
It was found that for a constant scratching depth, both the average normal force and friction force were much larger for single-crystalline silicon compared to polycrystalline silicon

Summary

Introduction

Silicon has been the material most commonly used in microelectromechanical systems (MEMS). Most of the studies in the literature have focused on the mechanical and wear behaviors of single-crystal silicon, some work has been done to study the deformation and wear process of polycrystalline silicon [13,14,15,21,22]. It is well-known that grain refinement is a promising way of improving the friction- and wear-resistance of metals [23,24]. In this work, MD simulations of the nanoscratching process of single-crystal and polycrystalline silicon using a diamond tool are performed to explore the effects of grain size on the wear behaviors of polycrystalline silicon

Simulation Details

Molecular

Results and Discussion

Conclusions