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Journal of Rare Earths 2024年第3期42卷 586-599,I0006页

作者： Zhen Li Wei Zhao Kedong Yu Ning Guo Guangchun Xiao Zhiming Wang Hui Zhang College of Mechanical Engineering Qilu University of Technology(Shandong Academy of Sciences)Jinan250353China Shandong Institute of Mechanical Design and Research Jinan250031China

The effects of Y_(2)O_(3) on the microstructure, microhardness, wear resistance, high-temperature oxidation resistance, hot corrosion resistance, and electrochemical corrosion behaviour of CoCrFeNiTiNb high entropy alloy coatings formed on Ti-6Al-4V alloy surfaces were studied. The results show that the addition of Y_(2)O_(3) changes the proportion of the phase but does not change its type. The average grain size is only 1/4.7 of that of the high entropy alloy(HEA) coating, and the fine-grained strengthening leads to increases in the microhardness and wear resistance of 21.8% and 26.9%, respectively. The addition of Y_(2)O_(3) enhances the denseness and bonding properties of the oxide and corrosion product layers, reducing the oxidation and hot corrosion rates by 60.3% and 40.3%, respectively. The addition of Y_(2)O_(3) doubles the corrosion resistance which is attributed to the refinement of the grains, the increased proportion of HCP and TiN, and the weakening of galvanic coupling corrosion.

关键词： laser cladding High entropy alloy coatings Rare earths Wear properties High temperature properties Electrochemical corrosion

Formation and properties of a Zr-based amorphous coating by laser cladding

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Rare Metals 2024年第4期43卷 1809-1814页

作者： Ning Zhang Ying Liu Wei Yang Shu-Jie Pang Key Laboratory of Aerospace Materials and Performance (Ministry of Education) School of Materials Science and EngineeringBeihang University

(Zr0.53Al0.1Ni0.05Cu0.3Ti0.02)99Y1（at%） coating with amorphous layer of about 180 μm thick was prepared on a steel substrate by using laser cladding method.The coating is compact and shows good metallurgical bonding with substrate.The microstructure,microhardness and corrosion behavior along the depth from the coating surface to the substrate were investigated.It is found that a gradient structure consisted of amorphous surface layer,amorphous-crystalline transitional layer and substrate is formed after the laser cladding.The microhardness and corrosion behavior exhibit variation with the microstructural evolution at different depths from the coating surface.The microhardness and corrosion resistance in 3.5 wt%NaCl solution of the amorphous surface layer are comparable to those of the as-cast Zr-based BMG with the same composition,and higher than those of the steel substrate.

关键词： laser cladding Amorphous coating Microstructure Hardness Corrosion resistance

Microstructure and Properties of AlCoCrFeNiTi High-Entropy Alloy Coatings Prepared by laser cladding

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Journal of Harbin Institute of Technology(New Series) 2024年第2期31卷 50-61页

作者： Mengxian Li Zhiping Sun Zhaomin Xu Zhiming Wang Qingdao ADR Axles Manufacturing Co. LtdShandong Qingdao 266400China School of Mechanical&Automotive Engineering Qilu University of Technology(Shandong Academy of Sciences)Ji'nan 250300China

21-4N(5Cr21Mn9Ni4N)is extensively employed in the production of engine valves,operating under severe conditions.Apart from withstanding high-temperature gas corrosion,it must also endure the impact of cylinder explosion pressure.The predominant failure mode of 21-4N valves is abrasive wear.Surface coatings serve as an effective approach to prevent such failures.In this investigation,laser cladding technology was utilized to fabricate AlCoCrFeNiTi high entropy alloy coatings onto the surfaces of 21-4N valves.According to the findings,the cladding zone has a normal dendritic microstructure,a good substrate-to-cladding layer interaction,and no obvious flaws.In terms of hardness,the cladding demonstrates an average hardness of 620 HV.The hardness has increased by 140%compared to the substrate.The average hardness of the cladding remains at approximately 520 HV even at elevated temperatures.Regarding frictional wear performance,between 400℃and 800℃,the cladding layer exhibits an average friction coefficient of 0.4,with the primary wear mechanisms being abrasive wear,adhesive wear,and a minor degree of plastic deformation.

关键词： high entropy alloy laser cladding microstructure microstructure and properties

laser cladding of NiCrSiB on Monel 400 to enhance cavitation erosion and corrosion resistance

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Rare Metals 2022年第12期41卷 4257-4265页

作者： Chun-Hua Zhang Chen-Liang Wu Song Zhang Yong-Feng Jia Meng Guan Jun-Zhe Tan Bin Lin School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China Nuclear Power Pump Industry Co. Ltd.Shenyang Blower Works Group CorporationShenyang 110869China

NiCrSiB modified layer was synthesized on Monel 400 by laser cladding,aiming at improving cavitation erosion and corrosion resistance.The microstructure,chemical composition,phase constituents and microhardness were investigated using scanning electron microscope(SEM),energy-dispersive spectrometer(EDS),X-ray diffractometry(XRD) and microhardness tester.The cavitation erosion and corrosion behaviors of the modified layer were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement,respectively.Experimental results show that by varying the laser fluence,a hard NiCrSiB modified layer with little airholes,cracks or other defects could be obtained.NiCrSiB modified layer is ~1.1 mm in thickness.The microstructure of the modified layer exhibits cellular dendrite,flake-like dendrite and multiple eutectic phase.The modified layer is mainly composed of γ-Ni solid solution,chromium carbide(Cr_(7)C_(3)and Cr_(23)C_(6)) and Ni_(3)B.The microhardness of the modified layer is ~6.8 times that of Monel 400 substrate.Both the cavitation erosion and corrosion resistance of the modified layer are improved.In the cavitation erosion test,the cumulative erosion loss and erosion loss rate of the modified layer are one order of magnitude lower than that of the substrate.In the electrochemical corrosion test,the corrosion potentials of the substrate and the modified layer are similar.The corrosion current densities of the substrate and the modified layer are 11.12 and 1.95 μA·cm^(-2),respectively.By comparing their corrosion current densities,the corrosion resistance of the modified layer is about 5.7 times that of the substrate.

关键词： NiCrSiB laser cladding Microstructure Cavitation erosion Corrosion

Excellent thermal shock resistance of NiCrAlY coatings on copper substrate via laser cladding

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Journal of Materials Science & Technology 2022年第35期130卷 93-102页

作者： Mingyu Gao Shunchao Li Weimian Guan Hongbin Xie Xiaoxiang Wang Jiabin Liu Hongtao Wang State Key Laboratory of Silicon Materials School of Materials Science and EngineeringZhejiang UniversityHangzhou 310027China Center for X-mechanics School of Aeronautics and AstronauticsZhejiang UniversityHangzhou 310027China

Coatings are widely used to protect substrates in extreme thermal environments(e.g., arc heaters), and thermal shock resistance is a crucial parameter for the coatings, which requires tight interlayer bonding between coatings and substrates. In this work, Ni Cr Al Y coatings were highly required for the pure copper substrate to restrict the electric arc in arc heaters. To overcome the bonding difculty of coating on the copper surface, the Ni Cr Al Y coatings were prepared by two laser cladding methods: conventional laser cladding(CLC) and high-speed laser cladding(HSLC). The microstructure, composition, and thermal shock resistance of Ni Cr Al Y cladding layers prepared by both methods were investigated. Benefitting from the high cooling rate and high energy density, the HSLC-layer has better composition uniformity and tighter interlayer bonding than the CLC-layer, achieving a 30%–45% improvement in thermal cycling lifetime. Besides, the Ni Cr Al Y layers prepared on copper substrate by both laser cladding methods exhibit3–10 times better thermal shock resistance than those Ni Cr Al Y layers prepared by conventional spraying methods. It further confirms the great effects of metallurgical bonding and composition uniformity on the thermal shock resistance of coatings. The Ni Cr Al Y layers fail in the form of internal cracking and interface peeling, and the corresponding failure mechanism is discussed.

关键词： laser cladding NiCrAlY Thermal shock resistance Microstructure

Enhanced microstructural and mechanical properties of Stellite/WC nanocomposite on Inconel 718 deposited through vibration-assisted laser cladding

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International Journal of Minerals,Metallurgy and Materials 2022年第2期29卷 327-334页

作者： Hossein Hosseini-Tayeb Seyed Mahdi Rafiaei Daneshpajoohan Pishro Higher Education Institute IsfahanIran Department of Materials Science and Engineering Golpayegan University of TechnologyGolpayeganIsfahanIran

Stellite-21/WC nanopowders were deposited on Inconel through vibration-assisted laser cladding with different laser parameters.Optical and scanning electron microscopy,hardness measurements,and wear characterizations were employed to understand the microstructural and mechanical behaviors of the nanocomposites.Results showed that varying the cooling rate exerted remarkable effects on the microstructure of the as-cladded composites.Moreover,increasing the laser power from 150 W to 250 W increased the heat input and the dilutions.Dilution was affected by the scanning rate and powder feeding rate at a high laser power of 250 W.When WC nanoparticles were added as reinforcement,the dilution magnitude intensified while the hardness value increased from HV 350 to HV 700.The wear characterizations indicated that the composites containing 3 wt%WC nanoparticles possessed the highest wear resistance.

关键词： Stellite WC nanoparticles mechanical properties laser cladding

The roles of microstructural anisotropy in tribo-corrosion performance of one certain laser cladding Fe-based alloy

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Friction 2023年第9期11卷 1673-1689页

作者： Weitao SUN Xuehong HUANG Jian ZHANG Bin WANG Xiaoliang LIU College of Mechatronics Engineering Binzhou UniversityBinzhou 256600China Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) Dalian University of TechnologyDalian 116085China College of Mechatronics Engineering Binzhou PolytechnicBinzhou 256600China

Because of the microstructural anisotropy for laser cladding materials,the tribo-corrosion performance can vary significantly with different directions.In this study,one certain Fe-based coating was fabricated by laser cladding.To study the effects of anisotropy,three working surfaces(0°,45°,and 90°to the building direction)were machined from the laser cladding samples;as-cast samples with an approximately homogeneous structure were prepared as controls.The tribo-corrosion tests were conducted in a 3.5 wt%NaCl solution with varying normal loads(5,10,and 15 N).The results demonstrated that the 45°surface has superior friction stability,corrosion resistance,and wear resistance.This was directly related to the crystal orientation and grain boundary density.In addition,a refined microstructure may enhance tribo-corrosion properties by increasing deformation resistance and decreasing surface activity.

关键词： laser cladding anisotropy Fe-based tribo-corrosion performance

Corrosion Resistance and Tribological Properties of laser cladding Layer of H13 Die Steel Strengthened by Ultrasonic Rolling

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 415-426页

作者： Kaikui Zheng Youxi Lin Jianguo Cai Chengqian Lei School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350116China School of Advanced Manufacturing Fuzhou UniversityJinjiang 362251China Mechanical and Electrical Engineering Practice Center Fuzhou UniversityFuzhou 350116China

laser cladding is a new surface repair method that can improve the wear and corrosion resistance of substrate surfaces.However,the cladding layer typically exhibits a rough surface,high hardness and large residual tensile stress,and thus requires further machining and finishing.Ultrasonic rolling(U-rolling)is a highly efficient finishing and strengthening process that combines ultrasonic technology with traditional rolling(T-rolling).In this study,an ironbased alloy was coated onto the surface of H13 die steel using laser cladding,and the surface of the cladding layer was polished using U-rolling.The effects of U-rolling on the surface quality,corrosion resistance and friction and wear properties of the laser-cladding layer were investigated and compared with those obtained by T-rolling.The surface roughness of the U-rolled sample was only 1/4 that of the T-rolled sample.The hardness and residual compressive stress of the laser cladding layer after U-rolling were higher than those after T-rolling.Similarly,the surface corrosion resistance of the laser cladding layer after U-rolling was higher than that after T-rolling.U-rolling changed the surface roughness,grain size,and residual stress of the material and thus affected the corrosion resistance of the laser cladding layer.The friction coefficient and wear rate of the U-rolled surface of the cladding layer were lower than those of the T-rolled surface.In addition,the tribological properties of the cladding layer were found to be related to the rolling direction.When the friction direction of the sample was the same as the rolling direction,its friction and wear performance were higher than those when the two directions were perpendicular.

关键词： laser cladding Ultrasonic rolling Surface quality Corrosion resistance Tribological properties

Wear and corrosion resistance of CoCrNi composite coatings by laser cladding

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China Foundry 2022年第6期19卷 535-543页

作者： Di Jiang Hong-zhi Cui Xiao-jie Song Xiao-juan Lian Xiao-feng Zhao Hao Chen Guo-liang Ma School of Materials Science and Engineering Shandong University of Science and TechnologyQingdao 266590China School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China

Two kinds of CoCrNi composite coatings,CoCrNiMo and CoCrNiMoBC,were prepared by laser cladding on the base metal of 304 stainless steel.The wear and corrosion properties of the coatings were studied by wear tests and electrochemical tests.Results show that the addition of B_(4)C promotes the generation of the ceramic phase,and therefore improving the microhardness of the coating and enhancing its wear resistance,while simutaneously keeps its excellent corrosion resistance.Energy dispersive X-ray spectrometry analysis shows that the chromium distribution in the two coatings is relatively uniform,which is beneficial for corrosion resistance.Scanning Kelvin probe microscopy results reveal that the potential difference between dendrites and interdendrites is only 20 mV,which leads to a relatively low driving force for galvanic corrosion.Observation through the atomic-scale high-resolution transmission electron microscopy shows that the fundamental reason for the high wear and corrosion resistance of the coating is the excellent coherent interface between the two phases,which reduces the interface energy and potential difference and thus improving its corrosion resistance.

关键词： wear corrosion laser cladding coherent boundary 304 stainless steel

Microstructure and wear resistance of AlCrFeNiMo_(0.5)Si_(x) high-entropy alloy coatings prepared by laser cladding

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China Foundry 2022年第6期19卷 473-480页

作者： Xiao-cong Li Hui Liang Yan-zhou Zhao Li Gao Li Jiang Zhi-qiang Cao Key Laboratory of Solidification Control and Digital Preparation Technology(Liaoning Province) School of Materials Science and EngineeringDalian University of TechnologyDalian 116024LiaoningChina School of Physics and Electronic Technology Liaoning Normal UniversityDalian 116029LiaoningChina

In recent years,the coating prepared by laser cladding has attracted much attention in the field of wear research.In this work,AlCrFeNiMo_(0.5)Si_(x)(x=0,0.5,1.0,1.5,2.0)high-entropy alloy coatings were designed and prepared on Q235 steel by laser cladding.The effect of Si content on microstructure,microhardness and wear resistance of the coatings was studied in detail.The results indicate that the AlCrFeNiMo_(0.5)Si_(x) highentropy alloy coatings show an excellent bonding between substrate and the cladding layer.The AlCrFeNiMo_(0.5)Si_(x) coatings are composed of nano-precipitated phase with BCC structure and matrix with ordered B2 structure.With the addition of Si,the white phase(Cr,Mo)_(3)Si with cubic structure appears in the interdendritic,and the morphology of the coating(x=2.0)transforms into lamellar eutectic-like structures.The addition of Si enhances the microhardness and significantly improves the wear resistance of the coatings.As x increases from 0 to 2.0,the average hardness of the cladding zone increases from 632 HV to 835 HV,and the wear rate decreases from 1.64×10^(-5) mm^(3)·(N·m)^(-1) to 5.13×10^(-6) mm^(3)·(N·m)^(-1).When x≥1.5,the decreasing trend of the wear rate gradually slows down.The wear rates of Si1.5 and Si2.0 coatings are 5.85×10^(-6) mm^(3)·(N·m)^(-1) and 5.13×10^(-6) mm^(3)·(N·m)^(-1),respectively,which is an order of magnitude lower than that of Q235 steel.

关键词： high-entropy alloy coatings laser cladding microstructure wear resistance