Attualità industriale - Metallurgia Additiva
AlTiN Coating of Ti6Al4V Alloy Additive Manufactured Parts S. Battiston, A. Fiorese, C.A. Biffi, F. Montagner, V. Zin, A. Gionda, J. Fiocchi, A. Tuissi AlTiN thin film deposition process was carried out via reactive Physical Vapor Deposition High-Power Impulse Magnetron Sputtering (PVD HiPIMS) with the aim of highlighting the criticalities which can occur during the coating Ti6Al4V parts realized via Selective Laser Melting (SLM). The conditions of PVD HiPIMS deposition process were adjusted in order to optimize the matching between the polished metallic substrates and the ceramic coatings. The effect of vacuum annealing at 950°C onto the coated sample features was also evaluated. X-ray Diffraction, Energy Dispersive Spectroscopy associated to Field Emission Scanning Electron Microscopy (FE-SEM), profilometry, and nanoindentation were employed for carrying out a complete characterization of the film/substrate system.
KEYWORDS: Ti6Al4V, SELECTIVE LASER MELTING, ADDITIVE MANUFACTURING, COATINGS, THIN FILMS, PVD HIPIMS.
INTRODUCTION Additive manufacturing (AM) is a family of bottom-up technologies that may answer to particular necessities, supporting the rapid fabrication of components with complex shapes. The most well-known advantages of AM are flexibility in the part design, possibility of realizing light parts, mechanical properties higher than those of conventionally casted materials and integration of different functionalities . Among the industrial AM 1
technologies, selective laser melting (SLM) is the most widespread, thanks to its process stability and its favorable ratio between costs and part quality. SLM is a powder bead process, in which a scanning laser beam can melt locally a limited portion of powder on the current layer. The process is replicated for several layers, therefore giving rise to near net shape 3D parts, manufactured through a layer by layer building strategy. Thanks to
S. Battiston, F. Montagner, V. Zin
National Research Council; Institute of Condensed Matter Chemistry and Technologies for Energy, CNR ICMATE, Padova, Italy.
A. Fiorese, A. Gionda
TAV VACUUM FURNACES SpA, Caravaggio (BG), Italy.
C.A. Biffi, J. Fiocchi, A. Tuissi
National Research Council; Institute of Condensed Matter Chemistry
and Technologies for Energy, CNR ICMATE, Unit of Lecco, Via Previati
1/E, 23900 Lecco, Italy. Corresponding author: carloalberto.biffi@cnr.it
the limited liquid pool size, very high cooling rates, up to 10 5-6 °K/s, are induced and this allows obtaining fine microstructures. However, the SLMed products require post-processing, like heat treatments for stress relieving, finishing for improving surface quality and controlling dimensional tolerances, and coatings for functiona-
La Metallurgia Italiana - febbraio 2020
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