Abstract No.:
2835

 Scheduled at:
Thursday, September 29, 2011, Saal C2.2 2:25 PM
Pre- & Post-Treatment 3


 Title:
Effect of laser remelting on the mechanical behavior of inconel 625 cold sprayed coatings

 Authors:
Simone Vezzù* / Veneto Nanotech , ITALY
Silvano Rech / associazione CIVEN, ITALY
Andrea Trentin/ associazione CIVEN, ITALY
Pedro Poza/ Departamento de Ciencia e Ingeniería de los Materiales, Spain
Claudio Munes/ Departamento de Ciencia e Ingeniería de los Materiales, Spain
M.A. Garrido/ Departamento de Ciencia e Ingeniería de los Materiales, Spain

 Abstract:
Ni base overlay coatings are being used to protect metallic engineering components in extreme conditions. Thermal spraying techniques, like Plasma Spraying (PS) and High Velocity Oxy-Fuel (HVOF), are currently used to deposit these systems. However, Coldspray is receiving increased attention during the last years because of the lower spraying temperature required to deposit metallic coatings avoiding oxidation and reducing the coating porosity and the amount of residual stress. The adhesion to the substrate and the growth mechanism of coldspray deposits is based on plastic deformation of impinging particles, so, in the case of high strength materials such as for example Ni alloys, it could be a lack in plastic deformation leading to insufficient compactness of the coating, barrier properties and high temperature resistance. Further improvements in the coatings performances could be attained by post-deposition thermal treatments to enhance coating adhesion and barrier properties.
In this sense, the aim of this study is to explore a two-step way to produce high performances Inco625 coatings by coldspray deposition followed by a laser glazing treatment. Coldspray Inco625 coatings has been deposited onto AISI304 steel substrates. Laser glazing is performed using a Nd:YAG pulsed laser (ROFIN Starweld 500); the local thermal treatment on the coating surface induce microstructural changes which will improve the coating compactness and performances. Coating morphology and microstructure has been evaluated and reported both before and after laser consolidation as a function of different laser conditions. Structural analysis has been performed in order to evaluate the effects of surface treatment. Finally, high temperature oxidation has been performed in order to evaluate and compare the coating performances and the benefits of the post-deposition surface treatment.


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