Effect of Nano-Y{sub 2}O{sub 3} on Microstructure and Crack Formation in Laser Direct-Deposited In Situ Particle-Reinforced Fe-Based Coatings

Journal Article · Thu Mar 15 04:00:00 EDT 2018 · Journal of Materials Engineering and Performance

DOI:https://doi.org/10.1007/S11665-017-2949-3· OSTI ID:22858064

Yin, Guili; Chen, Suiyuan; Liu, Yuanyuan; Liang, Jing; Liu, Changsheng ^[1]; Kuang, Zheng ^[2]

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1. Northeastern University, Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), School of Material Science and Engineering (China)
2. University of Liverpool, Laser Group, Centre for Materials and Structures, School of Engineering (United Kingdom)

In situ hard-particle-reinforced Fe-based composite coatings were prepared on Q235 steel substrates by direct laser deposition using Fe-based alloy powders containing 2 wt.% B, 3 wt.% Si and 1-3 wt.% nano-Y{sub 2}O{sub 3}. The microstructures, phase compositions, hardnesses and wear resistances of the deposited coatings with different nano-Y{sub 2}O{sub 3} contents were studied using metallographic microscopy, scanning electron microscopy, x-ray diffraction, transmission electron microscopy, microhardness tests and pin-on-disk abrasion tests (MMW-1A), respectively. The results showed that the appropriate addition of Y{sub 2}O{sub 3} played a role in grain refinement and in decreasing the number of brittle phases and impurity elements in the grain boundaries. Consequently, the number of cracks in the laser-deposited coating also decreased. The Fe-based composite coatings were mainly composed of α-Fe, γ-Fe and in situ-produced reinforced particle phases, such as Cr{sub 23}C{sub 6}, Cr{sub 7}C{sub 3}, (Cr, Fe){sub 7}C{sub 3}, Fe{sub 2}B, and CrFeB. When the content of nano-Y{sub 2}O{sub 3} was 2 wt.%, a Fe-based composite coating with a thickness of 4 mm that was free of cracks was obtained, and its surface hardness reached 650HV. Moreover, the wear resistance of the coating with 2 wt.% nano-Y{sub 2}O{sub 3} was the best among the samples studied. The presence of nano-Y{sub 2}O{sub 3} increased the solubility of Cr and Si in the solid solution, which eliminated the residual austenite region, and as a result, the phase transformation from γ-Fe to α-Fe was restrained and the transformation stress was also limited, thereby decreasing the probability of cracks in the coatings.

• OSTI ID: 22858064
• Journal Information: Journal of Materials Engineering and Performance, Journal Name: Journal of Materials Engineering and Performance Journal Issue: 3 Vol. 27; ISSN 1059-9495; ISSN JMEPEG
• Country of Publication: United States
• Language: English

Related Subjects

77 NANOSCIENCE AND NANOTECHNOLOGY
AUSTENITE
CHROMIUM CARBIDES
COATINGS
CRACK PROPAGATION
GRAIN BOUNDARIES
GRAIN REFINEMENT
IRON BORIDES
METALLOGRAPHY
MICROHARDNESS
NANOPARTICLES
PHASE TRANSFORMATIONS
SCANNING ELECTRON MICROSCOPY
SOLID SOLUTIONS
SOLUBILITY
STEELS
STRESSES
SUBSTRATES
THICKNESS
TRANSMISSION ELECTRON MICROSCOPY
WEAR RESISTANCE
X-RAY DIFFRACTION
YTTRIUM OXIDES