Molecular Dynamics Simulations Of Diamond Tool Groove Wear Hard Particles Scratching

During the process of nanometric cutting monocrystalline silicon, the groove wearhappening at the flank face of the diamond tool affects the quality of the workpieceseriously. But the mechanism of the groove wear hasn’t been revealed clearly. The thesisstudied the process of hard particles scratching at the flank face of the diamond tool basingon molecular dynamics simulation, analyzed the effect of hard particles scratching ongroove wear. The conclusion laid certain theoretical foundation for future research ofgroove wear theory and procedure.Firstly, assume that the hard particles are silicon carbide and diamond based on thepredecessors’ research. In order to study the effects of temperature on bonding strength ofsilicon carbide and diamond, the model of molecular dynamics simulation of siliconcarbide and diamond were established. Through simulating the changes of bond length ofC-C in diamond and Si-C in silicon carbide crystal in different temperatures, thengrouping the bond length by size and presenting the data in the form of frequencydistribution histogram, the thesis anlyzed the effect of different temperatures on the bondlength of C-C and Si-C detailedly. This phenomenon points to using silicon carbide hardparticles to scratch diamond crystal is theoretically possible.Assuming the hard particles to be a tool and diamond tool to be a workpiece, basedon the predecessors’ research, suppose that the form of scratch are mechanical scratchingand rolling scratching. The hard particles are hemisphere in the process of mechanicalscratching and are spherosome in the process of rolling scratching. Based on thisassumption, the model of molecular dynamics simulation of silicon carbide/diamondcarbon hard particles-diamond tool mechanical scratching/rolling scratching areestablished.Through simulating the process of hard particles scratching, analyzed the variation ofcutting force, average potential and temperature of the atoms in Newton layer, observedthe tool wear by the visualization software VMD, analyzed the causes of tool wearcombining the viewpoint of instantaneous distribution of atoms. By calculating the variation of coordination numbers of the tool atoms at differentmoments during the cutting process, quantified the groove wear and got the quantity ofworn atoms and wear rate at different moments. Analyzed the effect of different scratchingdepth, scratching speed, rolling scratching speed and other scratching parameters ongroove wear.