Study On Friction And Wear Characteristics Of TiC/Y₂O₃/TiAl Based Self-lubricating Joint Bearings

The joint bearings are special type of sliding bearings and have a wide range of applications in vehicle engineering,heavy machines and other fields.Friction and wear is one of the failure modes of joint bearings.And it becomes more serious under high temperature and heavy load.Therefore,it has great development prospects and practical value to develop the joint bearings with good friction and wear characteristics under high temperature conditions.In this paper,Ti-45Al-5Nb based alloy was used as the matrix,62%BaF₂-38%CaF₂?Abbreviation is BC?,TiC and rare earth oxide Y₂O₃ were added to prepare TiC/Y₂O₃/TiAl based joint bearings with strong bearing capacity,good wear resistance and self-lubricating properties under high temperature conditions.The contact mechanics of the joint bearing are analyzed.It is found that the stresses are mainly related to the structural sizes,load and material properties of the plian bearings.Analyze the contact stress of joint bearing models with different materials under radial,axial working conditions and the frictional stress under rotation by workbench.The results show that the TiC/Y₂O₃/TiAl based self-lubricating alloys can effectively improve the bearings capacity and friction and wear characteristics of joint bearings.The TiC/Y₂O₃/TiAl-based self-lubricating materials are designed by orthogonal test,prepared by vacuum hot pressing.Analysis of the test results,found that trace amounts of Y₂O₃ can effectively improve the microstructure and refine the grain size of the alloys,improve the physical and mechanical properties of the alloys.Added right amount of hard particles TiC can significantly improve the hardness and bending strength of the alloys.After added solid lubricant BC,the density and hardness of the alloys showed decrease.When the mass fractiones of Y₂O₃,TiC and BC is 0.25%,5%and 13%,respectively,the comprehensive performances of the new TiC/Y₂O₃/TiAl based self-lubricating alloys are excellent.The friction and wear tests of TiC/Y₂O₃/TiAl self-lubricating alloys are under high temperature.It is found that TiC and BC can effectively improve the friction and wear characteristics of the alloys,while Y₂O₃ has little effect.At 5%TiC,13%BC,the alloys exhibited good wear resistance.Under different working conditions to analysis TiC/Y₂O₃/TiAl self-lubricating alloys and determined the suitable working load and temperature of them.Design and manufacture TiC/Y₂O₃/TiAl self-lubricating joint bearing.Analyzed it's friction and wear characteristic at 600°C.Compared with ordinary joint bearing,the wear rate of TiC/Y₂O₃/TiAl based self-lubricating joint bearing increases with the increase of load,which is lower than ordinary joint bearing.The ordinary joint bearing friction and wear is much more serious than TiC/Y₂O₃/TiAl based self-lubricating joint bearing.It shows that TiC/Y₂O₃/TiAl based self-lubricating joint bearing have good friction and wear characteristics under high temperature conditions.