锆合金激光熔覆镍基复合层微观组织及界面特征
Microstructure and interfacial characteristics of Ni-based composite coating on zirconium alloy substrate by laser cladding
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摘要: 以Ni35自熔性合金粉末为熔覆材料，采用激光熔覆技术在锆合金表面原位生成了NiZr2/陶瓷增强镍基涂层.利用金相显微镜、扫描电镜、X射线衍射仪等对熔覆界面附近的微观组织、物相组成及界面结合特征进行分析.结果表明，熔覆层基体组织为NiZr+Ni10Zr7，增强相NiZr2以细针状均匀分布在熔覆层上部和底部，块状及棒状的陶瓷相Zr5（SixNi1-x）4/Zr（SixNi1-x）分布在熔覆层中部，熔覆层与基体间实现良好的熔焊冶金结合，界面结合区组织不均匀，分布有等轴状NiZr及晶间的α-Zr，熔覆层的显微硬度分布均匀，平均值约为1 100 Hv.Abstract: The NiZr2/ceramic reinforced Ni-based composite coating was in-situ synthesized by laser cladding using Ni35 self-fluxing powder on zirconium alloy substrate. The microstructure, phase constituents and interfacial characteristics were investigated by optical microscope, scanning electron microscope and X-ray diffraction method. Results indicated that the matrix of coating was mainly composed of NiZr+Ni10Zr7, fine needles NiZr2 distributed at the top and the bottom, and blocky Zr5(SixNi1-x)4/Zr(SixNi1-x) ceramic phase in the middle of the coating. Good metallurgical bonding between substrate and coating was obtained. Heterogeneous microstructure of interface zone was mainly compromised of equiaxial NiZr phase and α-Zr at the grain boundary. The mean value of microhardness of the coating reached 1 100 HV.
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[1] Kim J H, Lee M H, Choi B K, et al. Effect of the hydrogen contents on the circumferential mechanical properties of zirconium alloy claddings[J]. Journal of Alloys and Compounds, 2007, 431(1-2):155-161. [2] Wang L L, Hu X, Nie X. Deposition and properties of zirconia coatings on a zirconium alloy produced by pulsed DC plasma electrolytic oxidation[J]. Surface and Coatings Technology, 2013, 221:150-157. [3] Ni N, Hudson D, Wei J, et al. How the crystallography and nanoscale chemistry of the metal/oxide interface develops during the aqueous oxidation of zirconium cladding alloys[J]. Acta Materialia, 2012, 60(20):7132-7149. [4] Li J N, Gong S L, Sun M, et al. Effect of Sb on physical properties and microstructures of laser nano/amorphous-composite film[J]. Physical B, 2013, 428:73-77. [5] Sexton L, Lavin S, Byrne G, et al. Laser cladding of aerospace materials[J]. Journal of Materials Processing Technology, 2002, 122(1):63-68. [6] Vrancken B, Thijs L, Kruth J P, et al. Microstructure and mechanical properties of a novel β titanium metallic composite by selective laser melting[J]. Acta Materialia, 2014, 68:150-158.
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