Study on microstructure and properties of Ni-based alloy/Y2O3-deposited metals by laser cladding
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Laser cladding of Ni-based alloy/Y2O3 (Yttrium Oxide) powder on 6061 aluminum alloy was carried out using 3 kW CW Nd:YAG laser to strengthen and improve hardness and corrosion resistance of substrate. Metal matrix composite composed of aluminum substrate, Ni-based alloy, refining and dispersion strengthening Y2O3, and particle hardening W, Cr was obtained. The microstructure and morphology, phase identification, element diffusion, and composition analysis of the Ni-based alloy/Y2O3-deposited metal and deposited metals/6061 aluminum substrate interface were examined using scanning electron microscopy (SEM), Electron Probe Micro-analyzer (EPMA) with energy-dispersive spectrometer (EDS) analysis. The micro-hardness distribution and corrosion-resistance property were investigated also. The results showed: (1) with the addition of Y2O3, more fine microstructures consisted of isometric crystal, white acicular crystal, and fringe crystal, primary phases were mainly Ni3Al, NiAl, NiAl3, W, α-Al, and CrxC. (2) Micro-hardness of deposited metals was 780–1100 HV0.2 and distributed smoothly near interface. The corrosion rate of aluminum substrate was nearly twice that of deposited metals with addition of Y2O3.
KeywordsY2O3 Heat Affect Zone Aluminum Substrate Laser Cladding Clothe Layer
The authors acknowledge the support of Specialized Research Fund for Excellent Young Teachers of Shanghai, People’s Republic of China (Grant No. 06xpyq17), the Scientific Program of Science & Technology Department of Shanghai (Grant No. 061111034), the Youth Foundation of Shanghai University of Engineering Science (Grant No. 06-7), and Specialized funds from Shanghai Municipal Education Commission (No. 06zz79). Many thanks are given to Prof. Shun Yao, Dr. Xinhua Tang, Fenggui Lu, Hailiang Yu, and J. J. Ding from Welding Engineering Institute.