Study On Abrasive Wear Performance And Wear Mechanism Of Particle Reinforced WC_p/4Cr5MoSiV1 Composite Layer Fabricated By Laser Melt Injection

In the fields of petrochemicals,mining,and molds,the economic losses caused by wear are shocking.The wear protection of the surface of components and parts is an important technical way to increase the service life of the equipment.By introducing suitable second-phase hard particles,a particle reinforced metal matrix composite layer can be fabricated on the metal surface,which can significantly improve the surface wear resistance of the material.It is of great theoretical and practical significance to fabricate wear-resistant composite layers and study their wear properties and wear mechanisms under different wear conditions.In this study,the WC_p/4Cr5MoSiV1 particle reinforced metal matrix composite layer was prepared on the surface of low carbon steel by laser melt injection technology.Based on the analysis of the characteristics of the laser-melt-injection process,the phase composition and microstructure of the composite layer were studied.The wear properties of the composite layer under different wear conditions were tested,and the wear mechanism of the composite layer under different wear conditions was analyzed.An optimized parameter window for laser melt injection of a WC_p/4Cr5MoSiV1composite material layer was obtained via process experiments.The effect of process parameters on the morphology and particle distribution of the composite layer was studied.It was found that the matching of heat input and powder feed rate was the key to the preparation of high-quality composite material layers.The phase composition of the composite material layer was determined by XRD and SEM,and the microstructure characteristics and formation mechanism of the composite material layer WC particles and precipitated carbides were analyzed.Through the wear performance tests under different wear conditions,the wear characteristics of the composite layers were compared and it was found that the composite layers perform differently under different wear conditions.The wear resistance of MMCs is much higher than that of pure metals under plane wear conditions.And the wear resistance of MMCs is slightly higher than pure metal under the impact wear condition.Under the impact wear condition of high speed and heavy load,the weight loss of MMCs is comparable to that of pure metal.Under cyclic pressure stress wear conditions,the composite layer breaks down in a relatively short period of time and does not exhibit excellent wear resistance.Through optical microscope and SEM analysis,the wear mechanism of composite layers under different wear conditions was explored.The wear mechanism of composite layers is different under different wear conditions.Under the plane wear condition,the wear of the composite layer is dominated by abrasive wear.The“shadow effect”of the reinforcing particles greatly enhances the wear performance of the composite layer;under the impact wear condition,the wear of the composite layer includes the deformation as well as wear of the metal matrix and the breaking as well as shedding of the raised WC particle.The maximum depth of the cracking particles is about 0.4mm.The wear of the composite layer under impact wear condition of high speed and heavy load includes the wear of the metal matrix and WC particle breakage.The maximum depth of occurrence of cracking particles is about 0.8mm.Under cyclic compressive stress wear conditions,the wear of the composite material layer is mainly destructive:During the wear process,the WC particles in the composite material layer first break down(cracked),and the crack progresses from particle to reaction layers and metal matrix.When the cracks connect into a network and expand to the surface,some MMCs fall off and the composite material layer is destroyed.