Preparation And Properties Of Ti₃AlC₂ Matrix Composites

The ternary layered compound Ti3AlC2 ceramic is the dual properties of metal and ceramic,is good electrical and thermal conductivity,relatively low hardness,plasticity at high temperature,machinability,and high strength and low density of ceramic materials.Excellent high temperature stability,excellent corrosion resistance,low friction coefficient and good self-lubricating properties.It is a pantograph material with potential applications.In this paper,Ti3AlC2 ceramics is used as the matrix material,Cu and graphene are used as strengthening phases respectively,and Ti powder,Al powder,TiC powder and graphite powder are used as raw materials,and Cu and graphene and raw material powder are mixed by three-dimensional ball milling.Ti3AlC2 ceramics,Cu/Ti3AlC2 composite ceramics,graphene/Ti₃AlC₂ composite ceramics were prepared by vacuum hot pressing sintering,and the sintering temperature was 1400°C.The effects of different mixing schemes and holding time on the microstructure and phase composition hardness of Ti₃AlC₂ were investigated.The effects of Cu and graphene content on phase composition,microstructure,thermal shock resistance,wear resistance and electrical conductivity of Cu/Ti3AlC2 composite ceramics and graphene/Ti₃AlC₂ composite ceramics were investigated.The experimental results show that the compounding scheme of TiC:Ti:Al=2:1:1 is used for mixing,the holding time is 50min,the sintering pressure is 25MPa,and the prepared sample has higher content of Ti₃AlC₂ and better hardness.The results of phase composition,microstructure,thermal shock resistance,wear resistance and electrical conductivity of Cu/Ti₃AlC₂ composite ceramics show that when Cu is added as a strengthening phase,the phases are the same in all samples.Ti3AlC2 and TiC and Ti-Al,Cu-Al,Cu-Ti-Al intermetallic compounds are formed.When the molar ratio of Cu is0.5,the content of Ti₃AlC₂ is the highest in the sample,and the intermetallic compound formed is the least.The thermal shock resistance,wear resistance and electrical conductivity are higher than those of other experimental groups,and the intermetallic compounds formed affect the grain size of the sample.The results of phase composition,microstructure,thermal shock resistance,wear resistance and electrical conductivity of graphene/Ti₃AlC₂ composite ceramics show that when graphene is added as strengthening phase,all phases in the sample are added.The contents of Ti₃AlC₂ in samples with basic masses of Ti₃AlC₂ and TiC and mass fraction of0.05%and 0.2%were higher than those of other experimental groups.The addition of graphene plays a role in refining the crystal grains,and as the mass fraction of graphene increases,the grain size gradually decreases,and the density of the sample decreases.When the mass fraction of graphene is 0.05%and 0.175%,the thermal shock resistance of the sample is higher than that of other experimental groups.When the mass fraction of graphene is 0.1%,self-lubrication can occur when friction and wear occur,and wear resistance is higher than other experimental groups.The graphene mass fraction is the lowest resistivity when the mass fraction of graphene is 0.075%.