Research On Processing Mechanism Of Quartz Glass In Nanoscale Processes Based On The MD Simulation

With the development of the science technology,the requirement of the material performance and machining quality is increasingly demanding.Due to the excellent performance,the application of quartz glass is widely used in the field of optics.For example,many advanced equipments used the material of quartz glass.Because of the hard and brittle properties and the limitation of processing conditions,there is serious surface and subsurface damage such as the crack in the process of machining quartz glass.At present,the requirement of surface quality of quartz glass has reached to the nanometer level in a lot of fields.And there also many difficulties in the research on processing mechanism of quartz glass in nanoscale processes by the experiment.Therefore,the MD simulation can be a kind of references in the naon research of quartz glass,which has many advantages in many mechanical simulation methods.In the paper,the MD simulation is adopted to study the processing mechanism of quartz glass and some nanoindentation and nanoscratch experiments are conducted.To study the influence of different depth-radius ratio on the process of quartz glass,the model is established,the correctness of which is validated.Many factors such as chips,elastic recovery,temperature and grinding force are studied in the scratch simulation of quartz glass.When the tool radius is a preset value,with the increasing of the depth-radius ratio(h/r),chips,the system temperature and the grinding force increase gradually.When the grinding depth is a preset value,the value of h/r is smaller and the tool radius is bigger.In the condition,it will not be easy to produce the chips.With the same condition of the value of h/r,when the tool radius is bigger,the grinding depth is bigger.Eventually,it is easier to produce the chips.Multiple grinding processes is done on quartz glass,including no feed grinding processes and feed grinding processes.Surface topographies,damage layer thickness,surface density and hardness of the machined surface are analyzed.From the results of multiple no feed grinding processes,damage layer thickness decreases first,then increases.Eventually,it tends to be stable.After multiple processes,the surface density increases from 10.7% to 22.7%.The average density of the first no feed grinding process and the second feed grinding process is lower,and the damage layer of the second feed grinding process is more homogeneous.Besides,the changing trend of hardness is consistent with that of the damage layer density.At last,the nanoindenter is used to conducted the nanoindentation and nanoscratch experiments,and the surface topographies,normal force,and friction coefficient are analyzed.From the experimental results,there is no phenomenon of a pile of material in the scratching processes with different scratching depth.With the scratching depth increasing,the normal force is also increasing.There is mainly plastic deformation in the process of scratching quartz glass.And the normal force,the lateral force and the friction coefficient is very stable.And in the processes of multiple scratches on the same place,there are also no pile of material and the scratching processes are stable.