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laser cladding of Al+Ir powders on ZM5 magnesium base alloy

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Rare Metals 2007年第5期26卷 420-425页

作者： CHEN Changjun WANG Maocai WANG Dongsheng JIN Ren LIU Yiming State Key Laboratory for Corrosion and Protection Institute of Metal Research Chinese Academy of Sciences Shenyang 110016 China Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education College of Materials ＆ Metallurgy Wuhan University of Science ＆ Technology Wuhan 430081 China Shenyang Liming Aero-engine Corporation Shenyang 110043 China

laser cladding of preplaced Al ＋ Ir powders on a ZM5 magnesium alloy was performed to enhance the corrosion resistance of the ZM5 magnesium alloy. A metallurgical bond was obtained at the coating/substrate interface. The corrosion potential （Ecorr） of the laser cladded sample was 169 mV positive to that of the untreated ZM5 substrate,while the corrosion current （Icorr） was some one order of magnitude lower. The laser cladded sample,unlike the untreated ZM5 substrate,showed a passive region in the polarization plot. Immersion tests confirmed that the corrosion resistance of the laser cladded ZM5 sample was significantly enhanced in 3.5 wt.% NaCl solution. The Al-rich phases of AlIr,Mg17Al12,and Al formed in the cladding layer and the rapid solid characteristics were contributed to the improved corrosion behavior of the coating.

关键词： laser cladding magnesium alloys Ir corrosion

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 *** microstructure,chemical composition,phase constituents and microhardness were investigated using scanning electron microscope(SEM),energy-dispersive spectrometer(EDS),X-ray diffractometry(XRD) and microhardness *** cavitation erosion and corrosion behaviors of the modified layer were also evaluated using an ultrasonic vibrator and potentiodynamic polarization measurement,*** results show that by varying the laser fluence,a hard NiCrSiB modified layer with little airholes,cracks or other defects could be *** modified layer is ~1.1 mm in *** microstructure of the modified layer exhibits cellular dendrite,flake-like dendrite and multiple eutectic *** modified layer is mainly composed of γ-Ni solid solution,chromium carbide(Cr_(7)C_(3)and Cr_(23)C_(6)) and Ni_(3)*** microhardness of the modified layer is ~6.8 times that of Monel 400 *** the cavitation erosion and corrosion resistance of the modified layer are *** 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 *** the electrochemical corrosion test,the corrosion potentials of the substrate and the modified layer are *** corrosion current densities of the substrate and the modified layer are 11.12 and 1.95 μA·cm^(-2),*** 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

laser cladding of Cold-Work Tool Steel by Pulse Shaping

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Journal of Materials Science & Technology 2011年第8期27卷 707-713页

作者： Matej Pleterski Janez Tuek Tadej Muhic Ladislav Kosec Faculty of Mechanical Engineering University of Ljubljana Akereva cesta 6 TKC D.O.O. Trnovska Ulica 8 Faculty of Natural Sciences and Engineering University of Ljubljana Akereva Cesta 12

Repair welding of cold-work tool steels in cold is very risky and almost impossible by conventional processes. The application of pulse shaping in laser cladding with wire to avoid the solidification problems in relevant steel is demonstrated. The results show that sound remelting and/or cladding can be achieved by the right selection of laser parameters and pulse shape, i.e. long pulse duration, moderate pulse peak powers and ramped-down pulse shape. Despite the defects and softening in the cladding due to the formation of retained austenite, the cladding shows better wear resistance at lower loads compared to the heat-treated base material.

关键词： laser cladding Repair welding Tool steel Wear test

laser cladding of high-entropy alloy on H13 steel

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Rare Metals 2014年第6期33卷 727-730页

作者： Xiao-Tao Liu Wen-Bin Lei Jie Li Yu Ma Wei-Ming Wang Bao-Hua Zhang Chang-Sheng Liu Jian-Zhong Cui The Key Laboratory of Electromagnetic Processing of Materials Ministry of Education Northeastern University School of Materials and Metallurgy Northeastern University

High-entropy alloy layer up to 150 lm in thickness was formed on H13 substrate with a metallurgical bonding at the coating/substrate interface. Simple solid solution phases were formed in the coating layer with a typical microstructure composed of both dendrite and interdendrite. The microstructure at the top of the cladding zone consists of equiaxed grains while that at the bottom consists of columnar grains. The coating layer exhibits great enhancement in microhardness and wear resistance compared with the H13 substrate.

关键词： laser cladding High-entropy alloy Microhardness Wear rate

laser cladding of Ni-based alloy on copper substrate

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Journal of University of Science and Technology Beijing 2006年第4期13卷 329-332页

作者： Fang Liu Changsheng Liu Xingqi Tao Suiyuan Chen School of Material and Metallurgy Northeastern University Shenyang 110004 China

The laser cladding of Ni1015 alloy on Cu substrate was prepared by a high power continuous wave CO2 laser. Its microstructure was analyzed by optical microscope （OM）, scanning electron microscope （SEM）, and X-Ray diffraction （XRD）. The average microhardness of the cladding coating was Hv 280, which was almost three times of that of the Cu substrate （Hv 85）. OM and SEM observations showed that the obtained coating had a smooth and uniform surface, as well as a metallurgical combination with the Cu substrate without cracks and pores at the interface. With the addition of copper into the nickel-based alloy, the differences of thermal expansion coefficient and melting point between the interlayer and cladding were reduced, which resulted in low stresses during rapid cooling. Moreover, large amount of （Cu, Ni） solid solution formed a metallurgical bonding between the cladding coating and the substrate, which also relaxed the stresses, leading to the reduction of interfacial cracks and pores after laser cladding.

关键词： copper laser cladding nickel-based alloy solid solution

laser cladding Al-Si/Al_2O_3-TiO_2 Composite Coatings on AZ31B Magnesium Alloy

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Journal of Wuhan University of Technology(Materials Science) 2012年第6期27卷 1042-1047页

作者：崔泽琴 YANG Hongwei 王文先 WU Hongliang XU Bingshe College of Materials Science and Engineering Taiyuan University of Technology Key Laboratory of Interface Science and Engineering in Advanced Materials(Taiyuan University of Technology) Ministry of Education

To improve the wear resistance and corrosion resistance of magnesium alloys, a 5 kW continuous wave CO2 laser was used to investigate the laser surface cladding on AZ31 B magnesium alloys with Al-Si/Al2O3-TiO2 composite powders. A detailed microstructure, chemical composition, and phase analysis of the composite coatings were studied by scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, and X-ray diffraction （XRD）. The laser cladding shows good metallurgical bonding with the substrate. The composite coatings are composed of Mgl7Al12, Al3Mg2, Mg2Si, Al2O3, and TiO2 phases. Compared to the average microhardness （50HV0.05） of the AZ3 1 B substrate, that of the composite coatings （230HV0.05） is improved significantly. The wear resistances of the surface layers were evaluated in detail. The results demonstrate that the wear resistances of the laser surface-modified samples are considerably improved compared to the substrate. It also show that the composite coatings exhibit better corrosion resistance than that of the substrate in 3.5wt% NaCI solution.

关键词： AZ31B magnesium alloy laser cladding Al-Si/Al2O3-TiO2 composite coating wear resistance corrosion resistance

Corrosion behavior of Al_(0.4)CoCu_(0.6)NiSi_(0.2)Ti_(0.25) high-entropy alloy coating via 3D printing laser cladding in a sulphur environment

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Journal of Materials Science & Technology 2021年第1期60卷 197-205页

作者： Hongxia Wan Dongdong Song Xiaolei Shi Yong Cai Tingting Li Changfeng Chen Beijing Key Laboratory of Failure Corrosion and Protection of Oil/Gas Facility MaterialsDepartment of Materials Science and EngineeringChina University of Petroleum(Beijing)Beijing 102249China Institute of Advanced Wear&Corrosion Resistant and Functional Materials Jinan UniversityGuangzhou 510632China

High-entropy alloys(HEAs) are of great interest in materials science and engineering communities owing to their unique phase *** are constructed with five or more principal alloying elements in equimolar or near-equimolar ***,they can derive their performance from multiple principal elements ratherthan a single *** this work,three-dimensional printing laser cladding was applied to produce an Al_(0.4)CoCu_(0.6)NiSi_(0.2)Ti_(0.25) HEA *** experimental results confirmed that the laser cladding could be used to produce a thin coating of 120 μm in *** the high-temperature laser cladding process,some Fe elements diffused from the substrate to the coating,forming a combination of face-centred cubic and body-centred cubic phase *** HEA coating metallurgically bonded well with the *** to the increased dislocation density and number of grain boundaries,the HEA coating was harder and had a stronger hydrophobicity than X70 *** electrochemistry results showed that the HEA coating had better corrosion resistance than X70 *** oxides formed on the surface of the HEA coating had a certain protective ***,because of the laser cladding,the HEA coating generated *** future work,the laser cladding technology will be improved and heat treatment will be implemented to prevent formation of cracks.

关键词： High-entropy alloy coating(HEA coating) laser cladding Corrosion behaviour

Fabrication of barium-strontium aluminosilicate coatings on C/SiC composites via laser cladding

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Journal of Materials Science & Technology 2017年第2期33卷 166-171页

作者： Fengrui Jiang Laifei Cheng Jiaxin Zhang Yiguang Wang Science and Technology on Thermostructural Composite Materials Laboratory Northwestern Polytechnical University Xi'an 710072 China

Barium-strontium aluminosilicate （BSAS） and Si/BSAS coatings were fabricated on the surface of C/SiC composites via a two-step laser cladding process. The microstructure, mechanical properties, and the water vapor corrosion behavior of the samples were investigated. The BSAS coating was found to be tightly bonded to the substrate and only a few pores and microcracks were observed. The introduction of a silicon middle layer was revealed to reduce thermal stress and promote the healing of defects formed during the laser cladding process. To evaluate the corrosion resistance, the BSAS and Si/BSAS-coated C/SiC com- posites were exposed to an atmosphere of 50% H2O and 50% O2 at 1250 ℃. The resulting weight change and flexural strength were measured as a function of the corrosion time. The addition of the silicon middle layer below the BSAS top layer resulted in a better resistance to water vapor corrosion. Furthermore, the Si/BSAS-coated samples showed a lower weight loss and a smaller reduction in flexural strength than the BSAS-coated and the uncoated samples during water vapor corrosion. Thus, laser cladding is dem- onstrated to be an effective and feasible method to fabricate high-quality ceramic coatings on C/SiC composites. The introduction of a silicon middle layer can inhibit defect formation during the laser clad- ding process and protect the composite from water vapor corrosion.

关键词： Environmental barrier coating Barium-strontium aluminosilicate C/SiC composite laser cladding

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