超高速激光增材铁基复合涂层结构设计与性能研究OA

Critical nuclear power components operating in extreme environments characterized by high temperature,high pressure,and intense irradiation are susceptible to severe wear,necessitating the development of surface strengthening coat-ings with superior wear resistance.Laser additive manufacturing,distinguished by its rapid solidification and controllable heat input,offers an effective pathway for optimizing the microstructure and enhancing the performance of Fe-based com-posite coatings.This study investigates the comparative microstructural evolution and properties of Fe-based composite coat-ings fabricated via Extreme High-Speed Laser Cladding(EHLA)and Broadband Laser Cladding(EH-BLC).The results in-dicate that EH-BLC,benefiting from a more uniform energy distribution and a higher cooling rate,facilitates the formation of planar interlayer interfaces,a narrowed heat-affected zone(HAZ),and a refined equiaxed grain structure.Concurrently,the EH-BLC coating establishes a continuous and dense carbide network,whereas the EHLA coating is characterized by skeletal defects and fragmentation.Attributed to this intact and refined microstructure,the EH-BLC coating demonstrates a low and stable coefficient of friction(COF)along with reduced wear depth.Consequently,the dominant wear mechanism transitions from brittle spalling to mild ploughing and stable plastic flow.Furthermore,the EH-BLC coating exhibits supe-rior electrochemical performance,evidenced by a higher corrosion potential,a lower corrosion current density,and enhanced pitting resistance.Therefore,by constructing a microstructure featuring refined grains and a continuous hard-phase network,the EH-BLC process significantly enhances both wear and corrosion resistance,providing a reliable processing route for the engineering application of high-performance coatings on critical nuclear components.