目的 通过调控Nb元素含量,优化激光熔覆制备CoCrNiNbx中熵合金涂层的微观组织与综合性能,以获得兼具高硬度、优异耐磨性和卓越抗空蚀特性的表面强化涂层。方法 以316L不锈钢为基体,采用激光熔覆技术制备不同Nb含量的CoCrNiNbx（x = 0、0.2、0.4、0.6、0.8、1.0、1.2）中熵合金涂层。利用X射线衍射（XRD）分析物相组成与晶格畸变,结合扫描电子显微镜（SEM）和能谱分析（EDS）表征显微组织与元素分布,并通过电子背散射衍射（EBSD）分析晶粒尺寸及相分布特征;采用显微硬度计、纳米压痕测试、摩擦磨损试验及超声振动空蚀实验,系统评价涂层的力学性能、耐磨性与抗空蚀性能。结果 随着Nb含量增加,涂层结构由单一面心立方相（FCC）逐渐转变为面心立方 + 密排六方（FCC + HCP）双相结构,Nb元素在晶间显著偏聚并形成富Nb的HCP相,导致晶格畸变增强和第二相强化作用显著。涂层平均显微硬度随Nb物质的量比x增加呈现先升高后降低的变化趋势,在x = 0.6时达到峰值（689HV0.1）,约为基体的3.7倍,磨损性能亦表现出相同的变化规律。空蚀实验结果表明,CoCrNiNb1.0涂层具有最优的抗空蚀性能,其质量损失显著低于316L基体,抗空蚀能力实现数量级提升。结论 Nb合金化能够有效调控CoCrNiNbx激光熔覆涂层的组织特征与综合服役性能。当Nb物质的量比x = 1.0时,涂层在保持较高硬度和良好强塑性的同时,兼具优异的耐磨性与抗空蚀性,表现出较为均衡的综合服役性能。本研究为CoCrNi基中熵合金涂层在高流速液体冲击环境下的工程应用提供了实验依据和工艺参考。
Abstract
Cavitation erosion and wear failure critically limit the service life of flow-passing components such as pump impellers, turbine blades, and propeller systems which are frequently subjected to high-speed liquid impact and cyclic flow-induced stresses. To address this challenge, the work aims to design a high-performance surface coating with enhanced hardness, wear resistance, and cavitation erosion resistance by tailoring the Nb content in a CoCrNi medium-entropy alloy (MEA) system. CoCrNiNbx (x = 0, 0.2, 0.4, 0.6, 0.8, 1.0, and 1.2) coatings were fabricated on 316L stainless-steel substrates with an FL020 fiber laser under identical processing parameters. The effect of Nb addition on the phase constitution, microstructure, mechanical properties, tribological behavior, and cavitation performance of the coatings was comprehensively investigated to determine the optimal composition for balanced mechanical and anti-erosion properties. Phase analysis by X-ray diffraction (XRD) showed that increasing Nb content promoted a transition from a single face-centered cubic (FCC) solid solution to a dual FCC + hexagonal close-packed (HCP) phase structure. The emergence and growth of the Nb-rich HCP phase were accompanied by pronounced lattice distortion and precipitation strengthening. Microstructural characterization using field-emission scanning electron microscopy (SEM) combined with energy-dispersive spectroscopy (EDS) revealed that Nb preferentially segregated along interdendritic regions, where fine HCP-phase precipitates gradually formed a semi-continuous strengthening network. Electron backscatter diffraction (EBSD) analysis further confirmed that Nb addition significantly refined the grain structure and altered the phase distribution, providing quantitative evidence for the heterogeneous dual-phase microstructure. Mechanical tests demonstrated that the coatings exhibited a non-monotonic hardness evolution with the increasing Nb content. The average Vickers microhardness firstly increased and then decreased, reaching a maximum of 689HV0.1 at x = 0.6, approximately 3.7 times that of the 316L substrate. This improvement was attributed to the combined effects of solid-solution strengthening induced by Nb addition and precipitation hardening associated with Nb-rich HCP phases. However, excessive Nb addition (e.g., x = 1.2) resulted in brittle phase aggregation and a slight reduction in hardness. Nanoindentation measurements were further conducted to evaluate the localized mechanical response of the coatings, revealing that Nb-containing coatings, particularly Nb1.0 exhibited a favorable combination of hardness and elastic compliance, indicative of enhanced energy absorption capability under concentrated loading. Tribological experiments using a reciprocating wear tester against Si3N4 balls in deionized water showed that the specific wear rate decreased initially and then increased slightly with the increasing Nb content. The Nb0.6 coating achieved the lowest wear rate (8.665 × 10-5 mm3·(N·m)-1), which was consistent with its high hardness and refined microstructure. In contrast, cavitation erosion tests performed for 12 h revealed that the Nb1.0 coating exhibited the best cavitation resistance, with a cumulative mass loss of only 2.8 mg and an average erosion rate of 0.233 3 mg/h representing an improvement of approximately 26 times over the 316L substrate and 20 times over the Nb0 coating. Surface morphology analyses confirmed that appropriate Nb incorporation effectively suppressed cavitation pit formation, mitigated fatigue crack initiation, and prevented large-area material spalling. The enhanced cavitation erosion resistance was attributed to the synergistic effects of solid-solution strengthening, refined dual-phase microstructure, and the semi-continuous distribution of Nb-rich HCP phases, which facilitated load redistribution and impact energy dissipation under high-frequency cavitation loading. Moderate Nb addition (x = 0.6-1.0) enabled an effective balance between strength and toughness, whereas excessive Nb content led to phase continuity and localized stress concentration, resulting in increased brittleness and degradation of erosion resistance. In summary, Nb alloying effectively enhances the microstructural stability and mechanical integrity of CoCrNi MEA laser-cladded coatings. An Nb content of x = 1.0 provides the optimal overall performance by combining high hardness, good wear resistance, and superior cavitation erosion resistance. These findings confirm the feasibility of Nb-alloying strategies for developing high-durability MEA laser-cladded coatings and provide valuable guidance for the design of long-life protective layers in flow-bearing and high-impact engineering components.
关键词
激光熔覆 /
CoCrNi中熵合金 /
Nb合金化 /
HCP相 /
涂层 /
硬度与耐磨性 /
空蚀
Key words
laser cladding /
CoCrNi medium-entropy alloy /
Nb alloying /
HCP phase /
coating /
hardness and wear resistance /
cavitation erosion
{{custom_sec.title}}
{{custom_sec.title}}
{{custom_sec.content}}
参考文献
[1] SUN J, GE X F, ZHOU Y, et al.Research on Synergistic Erosion by Cavitation and Sediment: A Review[J]. Ultrasonics Sonochemistry, 2023, 95: 106399.
[2] LI X W, LIU H Y, GUO W L, et al.Effect of TiO2 Content on the Thermal Control Properties of Al2O3-xTiO2 Composite Coatings Prepared by Supersonic Plasma Spraying Technology[J]. Journal of Materials Research and Technology, 2024, 32: 3582-3593.
[3] WANG Y F, SHI X S, GAO J, et al.Surface Crack Propagation of Electroplated Chromium Coating and Cotton Fabric with Dry Friction[J]. Engineering Failure Analysis, 2024, 163: 108485.
[4] QIU L C, CHEN H, ZENG F F, et al.Microstructure, Mechanical Properties and Cutting Performance of Super-Hard Ti(B, C, N) Coatings Prepared by Chemical Vapor Deposition Method[J]. Surface and Coatings Technology, 2024, 480: 130599.
[5] TORABI S, GHASEMI R, SHAHRABI FARAHANI A, et al."Modeling, Microstructural Characterization, Mechanical and Corrosion Properties of the CrN/CrAlN Multilayer Coating Produced by Physical Vapor Deposition."[J]. Ceramics International, 2024, 50(12): 21451-21462.
[6] LI J H, YANG Y H, YAO F P, et al.Effect of Laser Remelting on Internal Defects and Properties of Ni-Based Coatings Reinforced by Multi-Channel WC in Situ[J]. Materials Today Communications, 2024, 38: 108375.
[7] NDUMIA J N, KANG M, BELLO Z A, et al.Microstructure and Wear Mechanism of FeCrMoCBWNb Coating Deposited by Arc-Spraying and Its Application on 65Mn Steel Blades[J]. Surface and Coatings Technology, 2024, 492: 131195.
[8] KUMARI R, KUMAR S, DAS A K, et al.Microstructural Characterization and Corrosion Analysis of HA/TiO2 and HA/ZrO2 Composite Coating on Ti- Alloy by Laser Cladding[J]. Applied Surface Science Advances, 2024, 24: 100655.
[9] WANG H N, CHENG Y H, WAN Y X, et al.Influence of Scanning Speed on Microstructure and Corrosion Resistance of Fe-Based Amorphous Coatings by High-Speed Laser Cladding[J]. Surface and Coatings Technology, 2024, 479: 130449.
[10] ZHANG Y S, LIU Z G, LV Z H, et al.Effect of SiC and TiC Content on Microstructure and Wear Behavior of Ni-Based Composite Coating Manufactured by Laser Cladding on Ti-6Al-4V[J]. Wear, 2024, 552: 205431.
[11] GAO Z S, XUE J K, OUYANG C S, et al.Investigation of the Microstructure and Tribological Properties of Laser Cladding 5%Ti3SiC2 Reinforced Co-Based Composite Coatings under Different Loads over the Wide Temperature Range[J]. Results in Engineering, 2024, 24: 103142.
[12] ZHANG T G, YAN X H, ZHEN H, et al.Influence of Cu Addition on the Microstructure and Tribological Properties of Ti-Based Laser Cladded Composite Coatings on TC4[J]. Materials Today Communications, 2024, 40: 110220.
[13] YANG Y F, HU F, XIA T, et al.High Entropy Alloys: A Review of Preparation Techniques, Properties and Industry Applications[J]. Journal of Alloys and Compounds, 2025, 1010: 177691.
[14] LIU J H, LV Z J, WU Z F, et al.Research Progress on the Influence of Alloying Elements on the Corrosion Resistance of High-Entropy Alloys[J]. Journal of Alloys and Compounds, 2024, 1002: 175394.
[15] 焦文娜, 卢一平, 曹志强, 等. 共晶高熵合金的研究进展及展望[J]. 特种铸造及有色合金, 2022, 42(3): 265-274.
JIAO W N, LU Y P, CAO Z Q, et al.Progress and Prospect of Eutectic High Entropy Alloys[J]. Special Casting & Nonferrous Alloys, 2022, 42(3): 265-274.
[16] 陈刚, 罗涛, 沈书成, 等. 难熔高熵合金的研究进展[J]. 材料导报, 2021, 35(17): 17064-17080.
CHEN G, LUO T, SHEN S C, et al.Research Progress in Refractory High-Entropy Alloys[J]. Materials Review, 2021, 35(17): 17064-17080.
[17] CHENG J, MA Y J, WANG X T, et al.Grain Refinement and Precipitation Synergistic Strengthening in CuMnNiTix Medium-Entropy Alloys[J]. Materials Science and Engineering: A, 2025, 922: 147659.
[18] ZHOU X B, MA D P, WANG Z W, et al.Enhancing Microbiological Corrosion Resistance of VCoNi Medium-Entropy Alloy via Thermo-Mechanical Treatments[J]. Corrosion Science, 2024, 235: 112210.
[19] LIU X Z, ZHOU Y, DONG H, et al.Microstructure and Properties of the Welding Heat-Affected Zone in CoCrNi Medium-Entropy Alloy[J]. Journal of Materials Research and Technology, 2024, 33: 6867-6875.
[20] AN N, SUN Y N, GAO L, et al.Long-Term Structural Stability and Excellent Mechanical Properties of CoCrNi System Medium Entropy Alloys[J]. Journal of Alloys and Compounds, 2022, 914: 165206.
[21] JI Y P, ZHOU D Z, JIANG D, et al.Wear and Wear- Corrosion Performance of CoCrNi-Based High-Entropy Alloys Modified by Mo and C under Ultrasonic-Assisted Laser Cladding[J]. Surface and Coatings Technology, 2025, 513: 132446.
[22] MA P C, PENG Y R, HU J, et al.Microstructure, Mechanical and Electrochemical Performance of Spark Plasma Sintered CoCrNi Medium-Entropy Alloy[J]. Journal of Alloys and Compounds, 2024, 1007: 176321.
[23] PAN S, ZHAO C C, WEI P B, et al.Sliding Wear of CoCrNi Medium-Entropy Alloy at Elevated Temperatures: Wear Mechanism Transition and Subsurface Microstructure Evolution[J]. Wear, 2019, 440: 203108.
[24] MA G L, CUI H Z, JIANG D, et al.The Evolution of Multi and Hierarchical Carbides and Their Collaborative Wear-Resisting Effects in CoCrNi/WC Composite Coatings via Laser Cladding[J]. Materials Today Communications, 2022, 30: 103223.
[25] HUANG L, ZHANG J Y, XIONG K, et al.Microstructure, Mechanical and Frictional Properties of CrCoNi- xNb Alloys Prepared through Powder Metallurgy[J]. Intermetallics, 2024, 175: 108496.
[26] XU Y H, WANG D Z, WU S J, et al.Research Progress on Defect Formation Mechanism and Process Optimization of Laser Cladding High Entropy Alloy Coatings[J]. Optics & Laser Technology, 2025, 187: 112819.
[27] LIU C G, QIU X W, PENG J, et al.Structure and Properties of Laser Cladding CoCrNi Multicomponent Alloy Coating Used in Rain Gauge[J]. Optics and Lasers in Engineering, 2023, 163: 107458.
[28] 偶国富, 周永芳, 郑智剑, 等. 空蚀机理的研究综述[J]. 液压与气动, 2012, 36(4): 3-8.
OU G F, ZHOU Y F, ZHENG Z J, et al.Review on the Mechanism of Cavitation Erosion[J]. Chinese Hydraulics & Pneumatics, 2012, 36(4): 3-8.
[29] LUO Q, ZHANG Q, QIN Z B, et al.The Synergistic Effect of Cavitation Erosion and Corrosion of Nickel- Aluminum Copper Surface Layer on Nickel-Aluminum Bronze Alloy[J]. Journal of Alloys and Compounds, 2018, 747: 861-868.
[30] LIU S S, ZHAO G L, WANG X H, et al.Microstructure Evolution and Property Regulation of CoCrNiNbx Laser Cladding Coatings[J]. Tribology International, 2024, 199: 110058.
[31] ZHANG F Z, LIU X B, CHEN G D, et al.Tribo-Corrosion Performance of Laser Cladding CuNiTiCrNb(h-BN)x High-Entropy Alloy Coatings[J]. Tribology International, 2026, 214: 111190.
[32] JIN H T, LUO F Y, CAI Y Q, et al.Effect of NbC Addition on the Microstructure and Properties of Laser Cladding CoCrNi Medium Entropy Alloy Coatings[J]. Surface and Coatings Technology, 2025, 515: 132615.
[33] 张颖隆, 张明赫, 李杰, 等. 高熵合金中晶格畸变效应的研究进展[J]. 热加工工艺, 2023, 52(4): 6-11.
ZHANG Y L, ZHANG M H, LI J, et al.Research Progress of Lattice Distortion Effect in High Entropy Alloys[J]. Hot Working Technology, 2023, 52(4): 6-11.
[34] 周文婷, 朱春霞, 李凡. 激光熔覆FeCoCrNiMnNb高熵合金涂层的组织及耐磨性[J]. 粉末冶金工业, 2024, 34(5): 105-110.
ZHOU W T, ZHU C X, LI F.Microstructure and Wear Behavior of Laser Cladding FeCoCrNiMnNb High Entropy Alloy Coating[J]. Powder Metallurgy Industry, 2024, 34(5): 105-110.
[35] XU Z L, ZHANG H, DU X J, et al.Corrosion Resistance Enhancement of CoCrFeMnNi High-Entropy Alloy Fabricated by Additive Manufacturing[J]. Corrosion Science, 2020, 177: 108954.
[36] ZHANG C, YA R H, SUN M, et al.In-Situ EBSD Study of Deformation Behavior of Nickel-Based Superalloys during Uniaxial Tensile Tests[J]. Materials Today Communications, 2023, 35: 105522.
[37] YU D T, ZHAO T, WU C L, et al.Effects of W Element on the Microstructure, Wear and Cavitation Erosion Behavior of CoCrFeNiMnWx High Entropy Alloy Coatings by Laser Cladding[J]. Materials Chemistry and Physics, 2024, 323: 129630.
[38] YANG J, ZHANG Z, CHEN X M, et al.Effect of Ti Content on Microstructure and Properties of Laser-Clad Fe-Cr-Ni-Nb-Ti Multi-Principal Element Alloy Coatings[J]. Materials, 2025, 18(17): 3985.
[39] WU P B, SUN S H, GUO P C, et al.Cavitation Erosion Characteristics and Mechanisms of Hydraulic Turbine Substrates and Their Coatings[J]. Ultrasonics Sonochemistry, 2026, 125: 107732.
[40] 王勇刚, 刘和剑, 王传洋, 等. 激光熔覆CoCrFeNi高熵合金涂层性能与空蚀行为[J]. 焊接学报, 2025, 46(12): 59-67.
WANG Y G, LIU H J, WANG C Y, et al.Properties and Cavitation Behaviors of CoCrFeNi High-Entropy Alloy Coating by Laser Cladding[J]. Transactions of the China Welding Institution, 2025, 46(12): 59-67.
[41] 杨聃, 李德红, 陈志雄, 等. 水轮机叶片激光熔覆抗汽蚀涂层性能研究[J]. 中国农村水利水电, 2022(4): 229-232.
YANG D, LI D H, CHEN Z X, et al.Research on the Properties of Anti-Cavitation Cladding Coating on Turbine Blades[J]. China Rural Water and Hydropower, 2022(4): 229-232.
[42] DING X Y, FU Y C, LI B, et al.Microstructure and Mechanical Properties of Al2O3 Dispersion Strengthened Cu by Laser In-Situ Aluminum Thermal Reduction Processing[J]. Materials & Design, 2025, 258: 114547.
[43] YU D T, WANG R, WU C L, et al.Effects of Laser Energy Density on the Resistance to Wear and Cavitation Erosion of FeCrNiMnAl High Entropy Alloy Coatings by Laser Cladding[J]. Materials Chemistry and Physics, 2025, 329: 130122.
[44] CHENG Y J, YANG H, ZHANG J, et al.Synergistic Strengthening and Anti-Erosion Mechanism of Laser Melting Deposited CoCrNiTix Medium-Entropy Alloys[J]. Journal of Alloys and Compounds, 2025, 1037: 182445.
[45] ZHANG H J, CHEN X Y, GONG Y F, et al.In-Situ SEM Observations of Ultrasonic Cavitation Erosion Behavior of HVOF-Sprayed Coatings[J]. Ultrasonics Sonochemistry, 2020, 60: 104760.
基金
国家自然科学基金（52375189, 52171035）
PDF(22891 KB)
渝公网安备 50010702501715号 渝ICP备15012534号-3
