This paper focuses on the performance of thin-film coatings onto additively manufactured Ti-6Al-4V. Specifically, because metal parts obtained by laser-powder bed fusion (L-PBF) often require post-process heat treatments and surface finishing to meet end-user specifications, we studied how the resulting changes to mechanical strength and surface roughness affect the performance of films deposited by physical or plasma-enhanced chemical vapor deposition (PVD, PE-CVD). L-PBF Ti-6Al-4V substrates were heat-treated either below or above the β-transus and finished by grinding with different grit sizes, and then were coated with PVD AlCrN or a PE-CVD DLC-based film. Scratch adhesion on harder surfaces treated below the β-transus was higher with both coating types, whilst the substrate finishing had a negligible effect. Conversely, in ball-on-disc sliding wear tests, substrate roughness had a dominant effect: rough surfaces always resulted in earlier cracking and delamination of the coatings. Substrate hardness had a minor effect only with the AlCrN film. Moreover, the DLC-based films, because of the low-friction conditions they establish through a graphitized tribofilm as well as their higher H/E ratio, survived severe contact conditions better than the stiffer AlCrN. The results were interpreted in the light of the plasticity indices of the coated systems and their tribochemical interactions.
Diamond-Like Carbon (DLC) and AlCrN films onto Ti-6Al-4V substrates by Laser-Powder Bed Fusion (L-PBF): Effect of substrate heat treatment and surface finish / Ghio, Emanuele; Bolelli, Giovanni; Bertè, Alessandro; Cerri, Emanuela. - In: SURFACE & COATINGS TECHNOLOGY. - ISSN 0257-8972. - (2023), p. 130128. [10.1016/j.surfcoat.2023.130128]
Diamond-Like Carbon (DLC) and AlCrN films onto Ti-6Al-4V substrates by Laser-Powder Bed Fusion (L-PBF): Effect of substrate heat treatment and surface finish
Ghio, Emanuele;Cerri, Emanuela
2023-01-01
Abstract
This paper focuses on the performance of thin-film coatings onto additively manufactured Ti-6Al-4V. Specifically, because metal parts obtained by laser-powder bed fusion (L-PBF) often require post-process heat treatments and surface finishing to meet end-user specifications, we studied how the resulting changes to mechanical strength and surface roughness affect the performance of films deposited by physical or plasma-enhanced chemical vapor deposition (PVD, PE-CVD). L-PBF Ti-6Al-4V substrates were heat-treated either below or above the β-transus and finished by grinding with different grit sizes, and then were coated with PVD AlCrN or a PE-CVD DLC-based film. Scratch adhesion on harder surfaces treated below the β-transus was higher with both coating types, whilst the substrate finishing had a negligible effect. Conversely, in ball-on-disc sliding wear tests, substrate roughness had a dominant effect: rough surfaces always resulted in earlier cracking and delamination of the coatings. Substrate hardness had a minor effect only with the AlCrN film. Moreover, the DLC-based films, because of the low-friction conditions they establish through a graphitized tribofilm as well as their higher H/E ratio, survived severe contact conditions better than the stiffer AlCrN. The results were interpreted in the light of the plasticity indices of the coated systems and their tribochemical interactions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.