Study On The Strength Plasticty And Frictionand And Wear Properties Of Graphene-reinforced Titanium Matrix Composites

In the past few years,with the widespread use of graphene(GNPs)/ Ti-based composite materials in the marine,aerospace,and aerospace fields,people have paid more and more attention to graphene-reinforced metal-based composite materials.For example: some researchers used plasma sintering to prepare titanium-based composite materials with discontinuously strengthened graphene nanosheets,which significantly improved the yield strength of the composite materials;Through research,it was found that graphene easily forms an anti-wear protective layer on the sliding contact interface,thereby reducing the friction coefficient of the composite material and so on.However,there are still problems such as uniform dispersion of graphene and poor interfacial bonding force of composite materials.In order to further improve the uniform dispersion and interface bonding force of the titanium-based composite material,so as to achieve the purpose of high-strength plastic matching and lubrication of the composite material.In this experiment,graphene raw material preparation process,plasma sintering process(SPS)was used to prepare graphene-reinforced titanium-based composite materials with higher density.The hot rolling and annealing(R&T)process of titanium materials was used to enhance graphene the interface bonding force of the titanium matrix refines the crystal grains and evenly disperses them.In order to obtain scientific data on the composition,microstructure and mechanical properties of the composite material,we used atomic particle microscope and laser confocal microscope to observe the surface roughness and three-dimensional morphology of the sample;using XRD and Raman The spectrum analyzer analyzes the phase composition of the composite material;SEM,EDS,EBSD,and TEM are used to characterize the composition and microstructure of the composite material;the electro-hydraulic servo digital material test tensile machine is used to study the tensile properties;Use a friction and wear tester to conduct tribological experiments and other studies.Experimental research shows that when the solid-phase reaction temperature is from 600 ℃ to 1100 ℃,the density of the prepared composite material increases from 82% to 98%.Tensile experiment research shows that under optimized SPS process and R & A process parameters,0.3w% GNPs titanium-based composite material at 850 ℃ can reach 1206 MPa,which is 46% higher than the pure titanium 825 MPa in the same state.It can also reach 48%,with excellent strong plastic fit.Its strengthening mechanism includes compound strengthening,fine grain strengthening and second phase strengthening.At 1100 ℃,the formation of nano-carbide particle layers resulted in a significant reduction in cross-sectional shrinkage.Friction and wear studies have shown that at low speeds,the formation of Ti O2 oxidized particles can be prevented by controlling the speed and pressure,and the friction coefficient of GNPs / Ti-based composites can be reduced from 0.65 to 0.2.This effect of reducing the friction coefficient is due to the fact that GNPs are prone to shear movement on the sliding contact interface and form a lubricating anti-wear protective layer,and graphene enhances the strength of Ti.The above experiments show that GNPs can indeed be used as effective short fibers in Ti to strengthen the titanium matrix,as a lubricating phase to reduce friction wear.Therefore,the experiment provides valuable research data for graphene reinforced metal matrix composites prepared by SPS.The experiment has the significance of evaluating GNPs as ideal reinforcing phase for pure titanium-based composite materials in SPS,R&T processes,and as a lubricating phase to reduce oxidative corrosion performance caused by friction and wear.