Research on the Mechanical Properties and Residual Stress of HVOF Sprayed Nanostructured WC-17Co Coatings

Abstract:

Nanostructured WC-17Co coatings, nanostructured WC-12Co coatings, conventional WC-17Co coatings were prepared by means of High Velocity Oxygen Flame (HVOF) technique. The characteristic of powders and coatings of nanostructured WC-17Co coatings, hardness of different coatings, distribution gradient of the hardness of the nanostructured WC-17Co coatings in the depth direction, fracture toughness and interface fracture toughness of different coatings, residual stress of different coatings, different phase and distribution of WC phase in the depth direction were investigated. The results indicated that the micro-crack is spread along the phase interface where the brittle phase are more in the Co rich area , where there are more different properties in the Co rich area and W rich area, where there are more defects close to the intend end in the W rich area, even spread through the WC particles in microcosmic and the different residual stress of different phase are because of different melting point and different expansion coefficient , so the WC, W₂C produced compressed stress, the Co₆W₆C produced tensile stress. The residual stress manifested from higher to lower in the depth direction of the coatings.

• Periodical: Advanced Materials Research (Volumes 291-294)
• Pages: 88-96
• DOI: https://doi.org/10.4028/www.scientific.net/AMR.291-294.88
• Online since: July 2011
• Authors: Guo Qing Gou, Nan Huang, Hui Chen, Da Li, Yan Liu, Hua Ji
• Keywords: Fracture Toughness, HVOF, Nanostructured, Residual Stress, WC-17Co

References

[1] H. Li. Young's modulus and fracture toughness determination of high velocity oxy-fuel-sprayed bioceramic coatings[J] . Surface and Coatings Technology 155 (2002) 21–32

DOI: 10.1016/s0257-8972(02)00026-9

[2] CHEN Hui，GOU Guo-qing，LIU Yan，TU Mingjing. Journal of Southwest Jiaotong University, 2008,43(5):633-637

[3] M.M. Lima. Coating fracture toughness determined by Vickers indentation: an important parameter in cavitation erosion resistance of WC–Co thermally sprayed coatings[J] . Surface and Coatings Technology 177 –178 (2004) 489–496；

DOI: 10.1016/s0257-8972(03)00917-4

[4] M.Watanabe, A.Owada, S.Kuroda, Y.Gotoh. Surf. Coat. Tech., 2006, 201: 619-627.

[5] E. Lo´pez Cantera. Fracture toughness and crack morphologies in eroded WC–Co–Cr thermally sprayed coatings [J] . Materials Letters 37_1998.201–210；

DOI: 10.1016/s0167-577x(98)00092-5

[6] Mustafa Toparl, Faruk Sen, Osman Culha, Erdal Celik. Thermal stress analysis of HVOF sprayed WC–Co/NiAl multilayer coatings on stainless steel substrate using finite element methods [J]. Journal of Materials Processing Technology, 190 (2007) 26–32

DOI: 10.1016/j.jmatprotec.2007.03.115

[7] J. Pina, A. Dias, J.L. Lebrun.Study by X-ray diffraction and mechanical analysis of the residual stress generation during thermal spraying[J]. Materials Science and Engineering,A347 (2003) 21-31

DOI: 10.1016/s0921-5093(02)00580-4

[8] J. Stokes, L. Looney. Residual stress in HVOF thermally sprayed thick deposits[J]. Surface and Coatings Technology, 177 –178 (2004) 18–23

DOI: 10.1016/j.surfcoat.2003.06.003