Study On Preparation Technology And Properties Of TiC Ceramic Particles Reinforced Molybdenum Composites

Due to the increasing weight-to-weight ratio of the engine,the environment inside the engine is getting worse and worse.The nickel-based superalloy cannot meet the higher temperature and pressure requirements.The molybdenum alloy has unique properties such as high melting point,excellent high temperature strength and good physical and chemical properties,so it is likely to become a more excellent high temperature alloy instead of nickel alloy.In this paper,TiC/Mo composites were prepared using pure Mo as the matrix and TiC ceramic particles as the reinforcing phase to study the effect of TiC ceramic particles content on the structure,mechanical properties and friction and wear properties of TiC/Mo composites,and study The effect of TiC ceramic particles on the high-temperature oxidation resistance of TiC/Mo composites is discussed.TiC/Mo composites prepared by spark plasma sintering technology have the advantages of fine grains and uniform structure.Mo and Mo2C are used as matrix phases in the alloy,where C mainly comes from the mold used in the sintering process,and the second phase particles are TiC Mainly,due to the higher melting point of TiC ceramic particles,as the amount of TiC ceramic particles increases,the relative density of spark plasma sintered TiC/Mo composites gradually decreases,up to 95.9%.TiC is evenly embedded in the matrix,which plays a role in strengthening and toughening the molybdenum matrix.Under the comprehensive influence of various factors,the mechanical properties of TiC/Mo composites are as follows:hardness and compressive strength are increasing with the increase of TiC ceramic particles.Rockwell hardness can reach up to 60.2HRC with the addition of TiC ceramic particles;compressive strength increased from 1015.71MPa to 1714.82MPa.The friction and wear test results of TiC/Mo composites with 5wt%TiC show that under low load,the material has a higher friction coefficient,and at high temperatures,the formation of oxidation products greatly affects the friction and wear performance As the test temperature increases,the oxidation process intensifies and the friction coefficient of the sample decreases.In the analysis of the oxidation of TiC/Mo composite and pure molybdenum at different temperatures,it was found that the oxidation product of TiC,Ti O₂,started to form at 1000?,which could inhibit the oxidation process to a certain extent.By oxidizing TiC/Mo composites with 5wt%TiC at 1200?for 60min,combined with the changes in the structure of the oxidation process,the following conclusions are drawn:Mo O₃ is produced in large quantities at the beginning of oxidation.A large amount of fine Ti O₂ particles are generated on the surface,that is,the mechanism of adding TiC ceramic particles to improve the high-temperature oxidation resistance of TiC/Mo composites.Among them,the fine Ti O₂particles will gradually wrap the flake Mo O₃ to form a smoother surface This reduces the number of pores,reduces the contact area between Mo and O₂,and reduces the oxidation rate.