Effect Of Multilayer Graphene And Fe₂O₃ Nanoparticles On Wear Behavior Of TC11 Alloy

Titanium alloys are widely used in various fields due to their excellent combination properties,but the poor wear resistance limits their applications.It is unavoidable that tribo-layers different from the matrix are formed on worn surfaces of alloys during dry sliding.However,scholars at home and abroadt put forwards different views concerning whether tribo-layers and tribo-oxides for titanium alloy can decrease the wear.Therefore,it possess theoretical significance and engineering values to explore the tribological performance of titanium alloys and the formation,function and mechanism of tribo-layers.In this paper,the mixtures of multilayer graphene and Fe₂O₃ nano-particles were added to the sliding interface of TC11alloy/GCr15 steel to improve the wear performances of titanium alloys.As a comparison,the wear behavior of TC11 alloy with no and pure multilayer graphene or Fe₂O₃ additives were simultaneously studied.The phases,morphologies and compositions of the worn surfaces were systematically analyzed by the microscopic analysis methods of XRD,SEM and EDS.The characteristics of tribo-layers and their formation process and function were studied.The formation process,influential mechanism of tribo-layers and the wear mechanism and wear transition of TC11 alloy were also explored.The results show that the wear behavior was closely related to the additive types as well as revolutions and additive ratio.When pure multilayer graphene or Fe₂O₃nano-particles were added,the wear loss of TC11 alloy was much higher than that without additives.For the mixing additives of multilayer graphene and Fe₂O₃nano-particles with different ratio,irrespective of the mixing ratio,the wear loss of TC11 alloy was significantly decreased to be lower than that without additives at low revolutions.With an increase of the revolution,When the mixed ratio is 2:1,the wear loss is lower than the other ratio.It was noticed that the tribo-layers with different compositions were always formed on the worn surfaces,when various nano-particles were added.Their function would markedly affect the wear performances and wear mechanism of TC11alloy.The single-layer tribo-layer?insert-type?formed on the worn surface of TC11 alloy for no and pure multilayer graphene or Fe₂O₃ additives.This tribo-layer has not a protective effect,leading to the appearance of severe wear,and the main wear mechanism was adhesive wear and abrasive wear.The artificially supplied multilayer graphene and Fe₂O₃ nano-particles with different ratios produced the double-layer tribo-layer?cover-type?,whose upper and lower layer contained multilayer graphene-and Fe₂O₃-predominated components,respectively.The research revealed that the tribo-layers consisting of Fe₂O₃ nano-particles are protective,and can decrease the wear loss significantly.And the multilayer graphene-containing tribo-layers present a lubricated effect,and guarantee the stable existence of Fe₂O₃-containing tribo-layers.This double-layer tribo-layer possessed excellent protection effect for TC11 alloy by prevent metals from contacting.Hence,the wear of TC11 alloy is significantly decreased,and a severe-to-mild wear occurs.When the multilayer graphene and Fe₂O₃ nanoparticles were mixed at a ratio of 2:1,the lower wear loss is achieved as compared wth other ratos.This can be attributed to the fact that timely supplement of the enough multilayer graphene particles for the destroyed multilayer graphene layer,ensured the full utilization of the anti-wear properties of Fe₂O₃.It is surmised that the addition of multi-layer graphene and Fe₂O₃ nano-particle mixture induces the formation of the cover-type,double-layer tribo-layers.They can be used for titanium alloys under the severe sliding conditions of without implementing any prior surface treatment.