The Preparation Techniques And Performance Research Of VC/Fe Composite

In this article, combined with vacuum hot-pressing sintering, powder metallurgytechnology and in-situ synthesized method to manufacture VC/Fe composite. In thesintering shaping process, finished the carbonization reaction of vanadium and sinteringdensification at the same time, made the VC particles to reinforce the iron base compositematerials. Because of the hard particle phase is in-situ synthesized, the particle surfacehaven’t been polluted, avoided infiltrating bad with the matrix, the particle phase isgrowing in matrix, the thermodynamic stability is good.With the SEM observation for the surface topography of the organization, the fracturemorphology and the fracture cracks of the VC/Fe composite, then combined withmechanical property of VC/Fe composite in different process conditions and differentcomponents; we can set up a relationship about the process parameters, properties, andthe composition, we can find that:Changed the component of the material can affect the performance of materials, thedifferent content of VC will influence the performance and organization of VC/Fecomposite, when the quality score of VC is55%, the various performance are relativelygood, the hardness is7.78GPa, the relative density is93%, material of bending strengthand fracture toughness is1070MPa and16.17MPa.m1/2respectively. the differentcontent of RE will influence the performance and organization of the VC/Fe composite,with the changing of the contents of RE, when the content of RE is0.3%,the hardness ofthe materials is10.21GPa, it’s maximum; content of Cr will affect the performance andorganization of the VC/Fe composite, with the content of Cr increased, when the contentof Cr was6%, the biggest hardness value is12.03GPa, the enhancing range is54.62%;Fracture toughness l and bending strength of material is reduced.The sintering temperature and holding time can influence the mechanics propertiesand the microstructure of VC/Fe composite. Through the study found that: The sinteringtemperature influences the mechanics performance of VC/Fe composite. with thetemperature rising, the density of VC/Fe composite is difference, the density resolve theperformance, in1150℃, the properties are relatively good, hardness is7.78GPa, relativedensity is93%, bending strength and fracture toughness is supreme, the bending strengthand fracture toughness is1070MPa and16.17MPa.m1/2respectively; holding time caninfluence the mechanical properties, with the holding time rising, when the holding time is80min, the hardness is Max, it’s10.71GPa, the enhancing range is37.66%; Therelative density changes slower from60to100min; when the holding time is60minutes,fracture toughness and bending strength of material is16.17MPa·m1/2and1070MPa, it’sbetter than before.The properties of VC/Fe composite can be influenced by the sintering process: in theexperimental process, with the sintering temperature increased, the wear resistance of thematerial is first decreased and then increased, when the sintering temperature is1200℃the frictional factor is minimum, it’ s0.8; With the holding time rising, the frictionalfactor of material is first increased and then decreased, when the holding time is20min,the friction coefficient is minimum, it’s0.746; Through the analysis of the mechanicalproperties of the materials, we can know, if the hardness and the relative density of theVC/Fe composite is better, the wear resistance of the material will be better. The contentof VC can influence greatly for wear-resisting performance, when the content of VC was55%, the wear performance of material is better, the friction coefficient is0.916-0.918. Inthe experimental process, the different of the rubbing pair can influence the wearresistance of VC/Fe composite, Under the steel ring, with the normal load increased,friction coefficient is firstly increases and then decreases, when the normal load is80N,the minimum friction coefficient is0.916; with the change of rotating speed, the faster thespeed, the bigger the friction coefficient When the speed is60r/min, the minimumfriction coefficient is0.918. Under the copper ring, with the experiment force’s increased,the friction coefficient decreased, when the normal load is100N, friction coefficient isminimum, it is0.468; with the rotating speed changed, the friction coefficient reducefirstly then increased, when the rotating speed is120r/min, the friction coefficient isminimum, it’s0.558. When VC content is55%, the friction coefficient are relativelybetter, they are0.918and0.916.The results show that: the higher the density and hardness,the better the wear resistance of material, the friction coefficient is lower; Through themicrostructure analysis can judged that, in the wear process, iron is off first, then theparticle phase, so VC grain can intensify the wear resistance.The study of VC/Fe composite is important for people to improve the materialsperformance, it can promote the materials’ development and application, and it’s usefulfor vanadium’s comprehensive utilization, it has important meaning to promote thedevelopment of regional economy.