Study Of Fabrication And Properties Of Ti₃SiC₂-TiAl Based Sliding Bearing Material

Sliding bearings are usually used for lubricant film failure,heavy load,low speed,high temperature and other harsh conditions.However,under the condition of high temperature,the use of the traditional sliding bearing material as bearing,usually due to poor lubrication caused by fatigue wear,scuffing,fatigue spalling failure.Under the condition of high temperature,the traditional sliding bearing materials have to meet the stiffness and strength requirements is not high enough,lubricating oil and grease under high temperature environment to be diluted,which not only pollute the environment,and the wear resistance of bearing materials can not meet the actual requirements of service conditions.Able to work under high temperature and vacuum environment,and has good bearing capacity,long wear life of aerospace lubricating materials have been developing field of aviation materials,is also facing great challenges.In this paper,the TiAl alloy matrix by adding Ti3 Si C2 as anti friction phase by plasma sintering?SPS?technology for preparation of high temperature self-lubricating bearing material,analysis of different self-lubricating materials relative structure,mechanical properties and friction performance,and to explore the self lubrication material the mechanism of reducing friction and lubricating film.?1?Compared to the alloy elements without adding alloying elements Cr or Nb after the hardness of TiAl alloy is improved obviously,and the addition of two kinds of alloy elements to enhance the most obvious effect;and different formula after sintering by the block density difference reached 99% or more;the addition of Cr or Nb single element can refine the microstructure of the Ti Al alloy,and the microstructure homogenization,but also add Cr and Nb instead of coarse grains are unevenly distributed,the increase of the content of alloy elements segregation at the grain boundary,the segregation of alloy elements and the main phase of the reaction product.The T2 or T3 formula should be chosen as the final matrix formulation.?2?The addition of Ti₃SiC₂ increases the hardness of the material,and it has obvious reinforcement,and the relative density of composite materials decreases with the increase of Ti3 Si C2.The friction coefficient of composites at room temperature at around 0.53,and the coefficient of friction under 550? at 0.43,the friction coefficient of composite materials under high temperature is lower than it The wear rate of composites at room temperature with Ti₃SiC₂ increases with the increment mass fraction,high temperature because of Ti₃SiC₂ is more likely to fall out from the matrix on the friction surface to form a layer of lubrication film so as to reduce the amount of wear and tear,composite material wear is greatly reduced.?3?At room temperature under different mass fraction of Ti3 Si C2,Ti Al-Ti₃SiC₂ composites were small friction coefficient,high temperature composite materials instead more low friction coefficient,room temperature conditions,the wear rate of the composite increases with the increment with Ti₃SiC₂ mass fraction,the composite materials under high temperature wear is greatly reduced and the difference is small;With the increase of sintering temperature,Ti Al matrix and lubrication phase combined with more solid two phase interface between Ti₃SiC₂,thus increasing the friction coefficient and wear rate of the composite material falling trend along with the sintering temperature appear drab.