Molecular Dynamics Study On The Sliding Tribology Behavior Of 304 Stainless Steel

Austenitic stainless steels are widely used in optics,biomedical,sensors,actuators,aerospace and nuclear industries due to their corrosion resistance,high thermal conductivity,biocompatibility,high ductility and high strength at high temperature.In austenitic stainless steel,due to the excellent flexibility,formability and corrosion resistance of 304 stainless steel sheet,it is widely used in nano-MEMS.With the further improvement of manufacturing precision requirements,In order to further expand the application range of 304 stainless steel in nano-electromechanical systems and explore the tribological properties of 304 stainless steel at the nanoscale,this paper established a rough body-plane 304 stainless steel sliding friction model at the nanoscale based on molecular dynamics simulation,and explored the The effects of different indentation depths(10,15,20 A)and different sliding friction velocities(0.5,1,1.5 (?)/ps)under fixed loads on wear morphology,number and distribution of wear atoms,friction force and subsurface damage Analyze its internal mechanism,and finally evaluate the tribological properties of 304 stainless steel under microscopic conditions with nano-scratch.The main conclusions of the paper are as follows:(1)With the increase of indentation depth,the number of wear atoms in the alloy tends to increase.When the indentation depth is 10 A,as the sliding friction progresses,the wear atoms cannot adhere to the front of the abrasive grains and flow to both sides of the wear scar;when the indentation depth is 20 A,the contact area between the abrasive grains and the alloy increases,and the wear The total adhesion between the particles and the wear atoms increases,and the wear atoms mainly accumulate in front of the abrasive particles,and wear the alloy together with the abrasive particles.(2)As the indentation depth increases,the dislocation density of the alloy increases during the friction process,and the deformation degree of the alloy increases.This is because the indentation depth increases,and the damage range of the abrasive grains to the alloy increases,resulting in more dislocations.Secondly,as the indentation depth increases,the frictional heat also increases,which will promote the nucleation of dislocations.(3)When the indentation depth is 10 A,as the sliding friction velocity increases,the dislocation density of the stainless steel alloy decreases,that is,when the sliding friction velocity is 1.5 (?)/ps,the alloy dislocation density is the smallest,because the sliding friction velocity The friction time is too short due to the increase of,and the dislocation density decreases.When the indentation depth is 15 and 20(?),the dislocation density of the alloy is the largest when the sliding friction velocity is 1.5 (?)/ps.This is because as the indentation depth increases,The increase in the area of abrasive grains in contact with the stainless steel alloy matrix leads to greater frictional heat,which is mainly due to the increase in temperature caused by friction and the increase in dislocation density.(4)In the nano-scratch test,as the load increases,the wear of the stainless steel surface is intensified,which is mainly manifested in the widening of the wear scar width and the increase of the average friction depth.This is because the larger load will cause the volume of the indenter to enter the stainless steel to increase.,aggravated the wear;after the indenter entered the stainless steel alloy,part of the wear debris accumulated on both sides of the scratch,which was similar to the molecular dynamics simulation results.