Abstract No.:
2660

 Title:
Effect of in-situ softening on the deposition behavior of particles through controlling gas stream traversing during cold spraying

 Authors:
Guan-Jun Yang* / School of Materials Science and Engineering, Xi'an Jiaotong University, China
Jun Wang/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
Chang-Jiu Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
Qiang Zhang/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China
Cheng-Xin Li/ State Key Laboratory for Mechanical Behavior of Materials, Xi'an Jiaotong University, China

 Abstract:
The deposition behavior of particles during cold spraying is determined by plastic deformation of both substrate and impinging spray particles. When a layer of coating is deposited, increasing the temperature of both spray particles and the underlying deposited particles enhances the deformation ability of both the substrate and impinging particles which is associated to the improved deposition efficiency. In this paper, the in-situ heating and subsequent softening of the local substrate were examined to reveal its influence on the deposition behavior of spray particles and the microstructure and property of the cold-sprayed coatings. 316L stainless steel powders were used to deposit coatings by cold spraying. Results show that the temperature of the substrate surface, where the spray gas stream and high velocity particles were projected on, increased to 300oC when the gas temperature was 500oC. Such effect is referred to as the in-situ heating of the substrate surface by spray gas stream. The in-situ heating of the substrate surface increased with the decrease in the traverse speed of the spray nozzle over substrate. With the increase of nozzle traverse speed from 20 to 100 mm/s, the relative deposition efficiency significantly decreased and the porosity of cold-sprayed 316L coatings increased from 2.5% to 5.6%, and the micro-hardness of the coatings decreased from 351Hv to 283Hv. The influence of the nozzle traverse speed on the microstructure and property of cold-sprayed coatings is discussed based on the influence of the in-situ heating of substrate surface on its deformation behavior by the impact of spray particles.

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