Tribology Design And Wear Resistance Research Of High Temperature Self-lubricating TiAl Matrix Composite Bearings

Ti-Al alloy is suitable for special fields such as aerospace because of its good hightemperature mechanics performance and high specific strength. But its application is limitedbecause of brittleness and poor wear resistance. In this paper, alloying method was used toimprove the mechanical properties, the toughness of Ti-Al matrix had been improved byadding the elements of Cr and Nb, the friction and wear properties had been improved byadding solid lubricants (CaF2, BaF2).Ti-Al matrix self-lubricating bearing composites with light and wear resistance werefabricated by the method of vacuum hot pressing sintering. The friction and wear performanceof the bearing composites were mainly studied by study of tribology design, materialpreparation, mechanical properties testing, research of friction and wear performance of thebearing composites.Bearing composites with well mechanical properties and friction and wear performancewere fabricated. And the composites density, bending strength, fracture toughness and othermechanical properties were studied. Research found that: the density of the compositematerials present a trend of first increases then decreases with the increase of solid lubricant;composites hardness decreased gradually with the increase of solid lubricant, when not addinglubrication, the substrate material of hardness is51HRC, while hardness was dropped to37HRC after adding15%solid lubricant. Within the lubricant additives of0~10%, bendingstrength and fracture toughness were increased as the adding of lubricant, while more than10%, the bending strength and fracture toughness were increased as the adding of lubricant.The friction and wear performance of self-lubricating Ti-Al matrix composites werestudied at room temperature and high temperature. The study found that the frictioncoefficient decreased with the increase of solid lubricant, CaF2and baF2has played a goodlubrication. Wear and friction performance at high temperature were better than roomtemperature. When10%and12%lubricant were added, friction performance was best. Under650℃, the wear rate and friction coefficient as the speed and load variation is studiedrespectively. Found that: the friction coefficient and wear rate increased with the increase ofrotational speed and load, the main wear form was abrasive wear, there were some surfacedeformation.Through Solidworks three-dimensional modeling and ANSYS simulation analysis in600℃,20MPa, the friction and wear performance of self-lubricating Ti-Al matrix compositesand GCr15(0.003-0.01mm hard chromium on the surface of sliding) were contrast studied. Friction and wear properties of Ti-Al material were extremely superior, after friction for aperiod of time, the highest temperature of Ti-Al composites was smaller nearly three timesthan hardened bearing steel, maximum stress value was2.5times smaller.