Molecular dynamics simulations of diffusion of carbon into iron

Abstract

Molecular dynamics (MD) simulations of diffusion couple tests were conducted between carbon (diamond/graphite) and iron at three different temperatures (300, 800 and 1600 K) and contact times (0, 40 and 80 ps) to investigate the chemical interaction between carbon and iron. Two different carbon structures, namely, diamond (cubic) and graphite (hexagonal), were considered. Diffusion of carbon into iron was observed only when a graphite interlayer was added to the diamond surface. When diamond alone was used, no diffusion was observed. This result provides corroborating evidence that diamond tool wear in the machining of iron occurs via a mechanism that involves an initial graphitization of diamond followed by diffusion of the newly formed graphite into the iron workpiece.

Keywords:

• machining
• cutting
• grinding
• diamond abrasive
• iron
• diffusion
• graphitization
• MD simulations
• wear

Acknowledgements

This project is funded by a grant from the National Science Foundation (DMI-0457663). We thank Dr Adnan Akay, Dr G. Hazelrigg, Dr Mary L. Realff and Dr Joycelyn Harrison of the Division of Civil, Mechanical, and Manufacturing Innovation (CMMI). RK thanks the A.H. Nelson, Jr. Endowed Chair in Engineering for additional support.