High temperature self-lubricating Ti-Mo-Ag composites with exceptional high mechanical strength and wear resistance  

作　　者：Yu Zhen Minghui Chen Chengtao Yu Zongbang Yang Yang Qi Fuhui Wang 

机构地区：[1]Shenyang National Laboratory for Materials Science,Northeastern University,Shenyang 110819,China [2]School of Mechanical Engineering,Ningxia Institute of Science and Technology,Shizuishan 753000,China [3]Lingyun Science&Technology Group Co.Ltd,Wuhan 430040,China

出　　处：《Journal of Materials Science & Technology》2024年第13期80-90,共11页材料科学技术（英文版）

基　　金：National Natural Science Foundation of China(No.51871051);Fourth Batch of Ningxia Youth Talents Supporting Program(No.TJGC2019028).

摘　　要：Titanium alloys are of keen interest as lightweight structural materials for aerospace and automotive in-dustries.However,a longstanding problem for these materials is their poor tribological performances.Herein,we designed and fabricated a multiphase Ti-Mo-Ag composite(TMA)with heterogeneous triple-phase precipitation(TPP)structure by spark plasma sintering.A lamellarα-phase(αL)precipitates from theβ-phase under furnace cooling conditions and maintains a Burgers orientation relationship(BOR)withβ-matrix.An active eutectic transition also occurs in the titanium matrix,resulting in TiAg phase.The intersecting acicular TiAg and lamellarαL cutβgrains into fine blocks and the primary equiaxedαphase also provides many interfaces withβphase,which together effectively impede dislocation move-ment and increase strength.Compared with other titanium composites,TMA with TPP microstructure gets an excellent combination of strength(yield strength 1205 MPa)and toughness(fracture strain 27%).Furthermore,the TPP structure endows TMA with strong cracking resistance,which aids in reducing abra-sive debris at high temperatures during sliding and obtaining a low wear rate.Simultaneously,Ag parti-cles distributed at grain boundaries will easily diffuse to the wear surface,in situ forming the necessary lubricating phase Ag_(2)MoO_(4) with Mo-rich matrix debris via oxidation.TMA possesses excellent tribologi-cal properties with especially low wear rate of 8.0 x 10^(-6)mm^(3)N^(-1)m^(-1) and friction coefficient(CoF)of merely 0.20 at 600℃.Unlike other self-lubricating composites with high volume fraction of soft ceramic lubricants,which inevitably sacrifice their mechanical strength and ductility,the composite TMA pos-sesses well-balanced strength,toughness and self-lubricating properties.It holds important implications to design other metal matrix self-lubricating composites(MMSCs)used for load-bearing moving parts.

关 键 词：TITANIUM High-temperature oxidation SELF-LUBRICATING Mechanical properties 

分 类 号：TB333[一般工业技术—材料科学与工程]