| AerMet100 steel has excellent comprehensive mechanical properties and high strength and toughness matching.It is mainly used to manufacture impact resistant components such as aircraft landing gear and structural armor.However,the tribological properties of AerMet100 steel are poor,which limits its wide application in industry.In the steel matrix,adding particle reinforcement phase and solid lubricating phase to prepare steel matrix composites can solve the problem of poor tribological performance,improve the performance of AerMet100 steel,and expand its industrial application range.In this paper,AerMet100 steel powder obtained by aerosolization method,and using it as matrix,WC and TiC as the particle reinforcement phase,and Mo S2 as the solid lubricating phase to prepare the AerMet100 composite material with excellent tribological properties through powder metallurgy process.The main research contents and results are as follows:(1)Different WC/AerMet100-based composite materials were prepared by powder metallurgy process.The sample with 10wt.%WC shows better performance whose hardness is 516.1HV,friction coefficient is 0.33,the wear rate is 2.66?10-5mm3·N-1m-1.The addition of WC increases the content of carbide hard phase in the matrix.These carbides are dispersed in the matrix,which effectively strengthen the material,improve the strength and hardness of the material,and provide effective support for the lubricating film.The material exhibits excellent mechanical properties and tribological properties.Through the analysis of the wear scar morphology of the sample,we can see that the wear mechanism of the sample is mainly fatigue wear,abrasive wear and oxidative wear.(2)Different WC/TiC/AerMet100-based composite materials were prepared by powder metallurgy process.When it contains 15wt.%WC and 5%wt.%TiC,the composites show hardness is 566.1HV,the average friction coefficient is 0.26,and the wear rate is2.23?10-5mm3·N-1m-1.The addition of TiC improved the wettability between the carbide hard phase and the metal matrix elements,refined the grains,and made the structure more uniform and compact.During high-temperature sintering,Ti elements and alloying elements Fe,Co and Ni form the solid solution has the effect of solid solution strengthening.The fine-grain strengthening effect of TiC not only increases the hardness of the composite material,but also not hurt the toughness.Through the analysis of the wear scar of the sample,we can see that the wear mechanism is mainly fatigue wear and abrasive wear.(3)In order to further improve the tribological properties of composite materials,different WC/TiC/Mo S2/AerMet100 composite materials were prepared by powder metallurgy process.When containing 15wt.%WC,5%wt.%TiC and 6.0wt.%Mo S2,the composite material has the best performance.Its hardness is 576.6HV,friction coefficient is 0.15,and wear rate is 1.35?10-5mm3·N-1m-1.The addition of Mo S2 can significantly improve the lubricating properties of composite materials.During the sintering process,part of Mo S2 will decompose,and part of Mo will form a solid solution with other metal elements,which has the effect of solid solution strengthening;the other part of Mo increases the content of carbides,further improving the hardness and bearing capacity of the composite material;S element reacts with Fe,Cr and other metal elements to form a low-shear strength lubricating phase such as CrxSx+1,Fe S,etc.During the grinding process between the friction pair ball and the sample,the carbide,lubricating phase and oxide are rolled together to form a layer of lubricating film,coated on the friction contact surface to play a self-lubricating effect and improve the tribological properties of the composite material.Observing and analyzing the morphology of the wear scar of the sample,it can be known that the wear mechanism at this time is mainly fatigue wear and abrasive wear. |
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