Investigations into the mechanism of material removal and surface modification at atomic scale on stainless steel using molecular dynamics simulation

Abstract

A molecular dynamics simulation (MDS) has been carried out to investigate the material removal phenomenon of chemo-mechanical magnetorheological finishing (CMMRF) process. To understand the role of chemical assisted mechanical abrasion in CMMRF process, material removal phenomenon is subdivided into three different stages. In the first stage, new atomic bonds viz. Fe–O–Si is created on the surface of the workpiece (stainless steel). The second stage deals with the rupture of parent bonds like Fe–Fe on the workpiece. In the final stage, removal of material from the surface in the form of dislodged debris (cluster of atoms) takes place. Effects of process parameters like abrasive particles, depth of penetration and initial surface condition on finishing force, potential energy (towards secondary phenomenon such as chemical instability of the finished surface) and material removal at atomic scale have been investigated. It was observed that the type of abrasive particle is one of the important parameters to produce atomically smooth surface. Experiments were also conducted as per the MDS to generate defect-free and sub-nanometre-level finished surface (Ra value better than 0.2 nm). The experimental results reasonably agree well with the simulation results.

Keywords:

• Nanofinishing
• CMMRF
• molecular dynamics simulation
• chemical-mechanical polishing
• abrasion

Acknowledgments

The authors acknowledge the support provided by Raja Ramanna Centre for Advanced Technology (RRCAT), Indore for AFM measurement. Authors are thankful to Dr Nageshwar Singh for AFM measurements at RRCAT, Indore (India), and would also like to express their appreciation to Mr Anuj Sharma of HBNI, Mumbai (India) for assistance in the support of MD simulation.