Preparation And Performance Study Of SLM Printed AlSi10Mg Framework Infiltrated Ptfe Self-lubricating Composite

With the development of industry,the demand for lightweight,high-strength and wear-resistant metal based self-lubricating materials is increasing.The self-lubricating materials such as stainless steel,copper and iron-based materials cannot meet the lightweight requirements of aerospace industry due to their high density.In order to provide a lightweight,high-strength,wear-resistant self-lubricating material for aerospace products.In this paper,the selection of matrix materials,the design of matrix structure,the selection of solid lubricants,the forming process and tribological properties are studied.The lightweight and high-strength AlSi10Mg is chosen as the matrix,and the hollow lattice structure is designed by means of structural enhancement.The metal skeleton is prepared by selective laser melting technology and filled with PTFE as lubricant.A new type of lightweight self-lubricating composite material with high strength and high strength was prepared by the combination of pressure-less infiltration and vacuum hot-pressing sintering.The effects of different loads on friction properties of AlSi10Mg-PTFE self-lubricating composites under three environments were studied,and the mechanism of the friction layer structure evolution in dry friction was explored.The following conclusions were drawn:(1)By Selecting Laser Melting(SLM),the skeleton of AlSi10Mg hollow lattice structure with high strength and high strength has been successfully prepared.By means of infiltration and vacuum hot-pressing sintering,the AlSi10Mg-PTFE self-lubricating composite material with high density and good bonding ability has been prepared.The compressive strength of.AlSi10Mg-PTFE self-lubricating composite material is 118 MPa,the thermal diffusivity fluctuates little with the increase of temperature and has thermal stability.(2)In dry friction environment,the friction coefficient of AlSi10Mg-PTFE composites increases first and then slightly lower with the increase of load.The wear rate increases first and then decreases with the increase of load.The lowest friction coefficient is 0.076,and the wear rate is the lowest 1.499 x 10^-5(mm³/(Nm).The average friction coefficient of composites increases first and then increases with the increase of load.The wear rate decreases first and then increases slightly with the increase of load.The lowest friction coefficient is 0.065,and the wear rate is the lowest 2.189 x 10^-4(mm³/(Nm)).The wear rate decreases first and then increases slightly with the increase of load.The lowest friction coefficient is 0.052,and the wear rate is the lowest 1.15 x 10^-4(mm³/(Nm).AlSi10Mg-PTFE composite has low friction coefficient and excellent wear resistance under three working conditions.In the three kinds of friction ring,the friction coefficient(COF)of the composite is:COF dry>COF water,>COF oil.The wear rate is K water>K oil>K dry.Under the condition of water lubrication and lubricating oil,the formation of PTFE film is hindered to varying degrees.(3)The study on the mechanism of the friction layer structure evolution in the dry friction condition indicates that under the action of load,the PTFE in the pores of the hollowed lattice structure will seep onto the friction surface and undergo partial transfer.A lubricant film will form between the friction pairs,which will reduce friction and wear and improve the wear resistance of the composite.