Heat Treatment of Metals ›› 2021, Vol. 46 ›› Issue (4): 176-181.DOI: 10.13251/j.issn.0254-6051.2021.04.032

• SURFACE ENGINEERING • Previous Articles     Next Articles

Shape memory effect of NiTi alloy coating deposited by high-velocityoxygen-fuel spraying

Duan Xueyan1, Li Wenli2, Qin Enwei1, Wang Bo1, Lu Haifeng1, Wu Shuhui1   

  1. 1. Division for Surface Technology and Engineering, Suzhou Nuclear Power Research Institute Co., Ltd., Suzhou Jiangsu 215004, China;
    2. School of Mechanical and Electric Engineering, Suzhou University, Suzhou Jiangsu 215004, China
  • Received:2020-10-11 Online:2021-04-25 Published:2021-05-08

Abstract: A highly dense NiTi alloy coating was prepared by high-velocity oxygen-fuel (HVOF) spraying, and the microstructure was optimized by subsequent aging treatment. The shape memory effects of the as-HVOF sprayed and as-aged specimens were evaluated through an indentation method. The OM and SEM microstructural characterization show that the as-sprayed NiTi coating consists of laminated internal island-chain interfaces, with a porosity of about 0.82%. The X-ray diffraction analysis shows that the as-sprayed NiTi coating owns 100% austenite, from which the Ni4Ti3 phase precipitates out in aging treatment. The indentation analysis shows that both the one-way and the two-way shape memory effects can be induced in the as-sprayed and the aged coatings, while the X-ray phase analysis and the differential scanning calorimetry analysis show that the shape memory effect is significantly increased by the precipitated second phase particles in aging treatment.

Key words: NiTi alloy, shape memory effect, high-velocity oxygen-fuel spraying, indentation method

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