Examinando por Autor "Verdi, Davide"

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Effect of the temperature on the microstructure and the mechanical properties of laser cladded Ni-based metal matrix composite coatings
(Universidad Rey Juan Carlos, 2015) Verdi, Davide
Las superaleaciones de base Ni se emplean habitualmente en aplicaciones donde la resistencia a la corrosión y a la oxidación resulta crítica para el correcto funcionamiento de un componente mecánico, como por ejemplo en la extracción de petróleo, en las minería, en las plantas termoeléctricas, en los motores de aviación, etc. Al mismo tiempo, la resistencia al desgaste de estas aleaciones es moderada. En aplicaciones como las anteriormente mencionadas, los diferentes componentes estáticos y dinámicos se encuentran sometidos a procesos de desgaste debidos por ejemplo a partículas duras, como óxidos, provenientes del exterior o generadas en el interior del sistema, que pueden golpear y arañar los diferentes componentes provocando averías indeseables [1]. Aplicar un recubrimiento cerámico representa la mejor solución para aumentar la resistencia a altas temperaturas de estos componentes, mejorando sus comportamiento frente al desgaste y la corrosión/oxidación...
Erosion behaviour of laser cladded Inconel 625 — Vanadium carbide metal matrix composites coatings manufactured with different reinforcement contents
(Elsevier, 2023) Verdi, Davide; Cortés, Rocío; Chia, Guo Yong; Tay, Grace
Erosive wear is a primary factor contributing to the potential failure of oil and gas components. Laser cladding of hard coatings constitutes one of the possible solutions to extend the components' service life. Among the viable options, the use of vanadium carbide reinforcement could provide a series of advantages. Vanadium carbide possess in fact similar hardness but significant lower density than other more conventional metal matrix composite's reinforcements. However, there has been limited work done in characterising the wear behaviour of such solutions in order to prove their viability. In this paper, the erosion behaviour of Inconel 625 – vanadium carbide metal matrix composite coatings deposited by laser cladding was investigated. Three different contents of reinforcement, 10, 20, and 30 wt%, were studied. Optical confocal microscopy was used to measure the coatings' volume loss after the tests performed with an air jet erosion tester following the ASTM G76 recommendations. The results were correlated with microstructural observations and hardness measurements. The generation of secondary carbides were detected in the coatings fabricated with 20 and 30 wt% reinforcement. In addition, a linear increase of the matrix hardness was observed while increasing the content of reinforcement in the coatings. On the other hand, the brittle behaviour of the primary vanadium carbide particles incorporated in the coatings becomes predominant for contents of 30 wt% reinforcement and reduces the coatings erosion resistance.
Metallisation of additive manufactured polyamide 12 by low pressure cold spray
(Elsevier, 2024-03-15) Verdi, Davide; Merino-Millán, David; Salazar, Alicia
Cold Spray is a solid deposition process that can expand the field of application of polymeric materials thanks to the build-up of a metallic coating that improves their electrical properties and the wear resistance, among others. The novelty of the Cold Spray deposition on polymers has as drawback the lack of processing models that allow to choose the manufacturing parameters and forecast the coatings and substrates properties. In this work, the influence of the processing parameters for Aluminium-Zinc coating build-up via Low Pressure Cold Spray on polyamide 12 additively manufactured via Fused Filament Fabrication was investigated. Several sets of processing parameters combinations were systematically modified to establish the deposition window, leading to a final set that allowed to determine the physical, microstructural, and mechanical properties of the coatings, and the physical and thermal properties of the polymeric substrate. For the fixed gas pressure of 0.45 MPa and gas temperature of 500 °C, the scanning speed and the powder mass flow rate had a strong influence. Thick coatings (around 850 μm in size) were achieved at high powder mass flow rate (26 g/min) at the expense of low bond strength (between 1 and 3 MPa). The surface roughness acquired the highest values in those samples where erosion took place, occurring this phenomenon at small standoff distances and low powder mass flow rate, and no finding any relationship with the transverse gun speed. The generation of an interface layer of mixed metallic particles polymeric substrate plays a key role in the subsequent metallic coating growth, with thicknesses that ranged from 30 μm to 200 μm. In the substrate, the crystallinity degree of the polyamide underneath the coating increased, evidence of a heat affected zone where temperatures around the crystallisation temperature were reached, that also promoted stretching of the polymeric substrate due to dilatational phenomena. All this accompanied of an overall decrease in the thickness of the PA12 coupon after coating build up deposition with the high powder mass flow rate. This evidence indicates that a large plastic deformation of the polymeric substrate at the most energetic combination of processing parameters took place