Molecular dynamics simulations of diffusion couple tests were conducted between carbon (diamond/graphite) and iron at 300, 800 and 1600K for contact times of 0, 40 or 80ps in order to investigate the chemical interaction between carbon and iron. Two different carbon structures, diamond (cubic) and graphite (hexagonal), were considered. The 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 diamondtool 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 workpiece.

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