Molecular dynamics simulations of diffusion couple tests were conducted between carbon (diamond/graphite) and iron at 300, 800 and 1600K and contact times (0, 40 and 80ps) 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 provided corroborating evidence that diamond tool wear in the machining of iron occurred via a mechanism that involved an initial graphitization of diamond followed by diffusion of the newly formed graphite into the iron work piece.

Molecular Dynamics Simulations of Diffusion of Carbon into Iron. Narulkar, R., Bukkapatnam, S., Raff, L.M., Komanduri, R.: Philosophical Magazine, 2008, 88[8], 1259-75