Preparation And Tribological Properties Of Ti₃SiC₂-TiC_0.4-TiAl Self-Lubricating Composites

TiAl materials are continuously applied to various fields of manufacturing due to their superior properties such as low density,but the high friction coefficient limits their application to moving parts.In this paper,a TiAl-based self-lubricating composite is studied by using TiAl as the matrix.Ti₃SiC₂ and TiC_0.4 are added to TiAl alloy,Ti₃SiC₂ is used as the lubricating phase,TiC_0.4 promotes sintering and strengthening the matrix,and the matrix and lubrication phase are more It is a good combination to reduce the wear of the Ti₃SiC₂ particles from the matrix,and to effectively reduce the friction coefficient and wear rate.It is proposed to solve the application of TiAl materials on moving parts.This topic firstly investigated the effect of TiC_0.4 content and Ti₃SiC₂ content on the properties of TiAl-based self-lubricating composites.The test results show that the hardness and density of TiAl-based self-lubricating composites increase gradually with the increase of TiC_0.4 content.The friction coefficient and wear rate at 25°C and 550°C are also improved,which is attributed to the higher hardness and TiC_0.4 to make the interface of the matrix and Ti₃SiC₂ more perfect,thus reducing the wear of the Ti₃SiC₂ particles from the matrix.,reducing its coefficient of friction and wear rate.The friction coefficient decreases and then increases with the increase of Ti₃SiC₂ content at 25°C.This is attributed to the excessive binding of Ti₃SiC₂ particles to the matrix.The Ti₃SiC₂ particles are slid and squeezed out of the relative sliding part and destroyed.The frictional oxide layer of the TiAl matrix,and thus the friction coefficient and the wear rate increase the hardness.The friction coefficient decreases with the increase of Ti₃SiC₂ content at 550°C,and then tends to be stable.Subsequently,the properties of TiAl-based composites with different particle sizes Ti₃SiC₂ containing 21-40 mesh,41-80 mesh and 81-120 mesh were studied.It is found that the larger particle size Ti₃SiC₂ is easy to get rid of the matrix during the sliding friction process,resulting in abrasive grain wear leading to an increase in friction coefficient and wear rate;too small particles are not easy to produce a slip lubrication layer,and Ti₃SiC₂ has the best performance when the particle size is 40-80 mesh..In addition,the sintering parameters of TiAl-based composites were investigated.The optimum sintering parameters were found to be 1100°C sintering temperature,100°C/min heating rate and 10 min holding time.Finally,the tribological properties of TiAl-based composites under different loads and different sliding speeds under optimal performance were studied,and the tribological mechanism was analyzed.It is found that its tribological properties are related to the load and sliding speed.The friction coefficient decreases first and then increases with the increase of the load,and decreases with the increase of the sliding speed.This is attributed to the easy sliding of the Ti₃SiC₂ particles at the high sliding speed.