A5086960048- Additive Manufacturing Materials and Processes
- Additive Manufacturing and 3D Printing Technologies
- Welding Techniques and Residual Stresses
- High Entropy Alloys Studies
- Advanced materials and composites
- Advanced Machining and Optimization Techniques
- Thermography and Photoacoustic Techniques
- Manufacturing Process and Optimization
- High Temperature Alloys and Creep
- Non-Destructive Testing Techniques
- Laser Material Processing Techniques
- Respiratory Support and Mechanisms
- Innovations in Concrete and Construction Materials
- High-Temperature Coating Behaviors
- Topology Optimization in Engineering
- COVID-19 diagnosis using AI
- Ultrasonics and Acoustic Wave Propagation
Universidade Nova de Lisboa
2019-2025
University of Lisbon
2023
In this study, we propose a new variant of wire and arc additive manufacturing (WAAM) based on hot forging. During WAAM, the material is locally forged immediately after deposition, in-situ viscoplastic deformation occurs at high temperatures. subsequent layer recrystallization previous solidification structure that refines microstructure. Because its similarity with forging, was named forging (HF-WAAM). A customized WAAM torch developed, manufactured, tested in production samples AISI316L...
This study evaluated the effect of dedicated heat treatments (1050°C, 1100°C, 1142°C, and 1185°C/2 h + double-aging) on uniaxial tensile properties at elevated temperature (650°C) Inconel® 718 fabricated via arc plasma directed energy deposition. They enabled to meet, for first time, AMS 5662 requirements temperature. Tensile tests exhibited ductile strain–stress curves. The 1100°C/2 double-aging showed best performance (YS0.2%, UTS, elongation 967 MPa, 1126 18.7%, respectively)....
Ni-based superalloy 718 fabricated via arc plasma direct energy deposition (IN718 AP-DED) exhibit a limited response to heat treatment due its coarse primary microstructure and interdendritic segregation, which may prevent use in high-integrity applications. Thus, dedicated treatments for IN718 AP-DED must possess homogenization temperature as high possible significantly dissolve the eutectics increase γ′′-former elements solid-solution. The present work proposed (homogenization – 1050,...
The study reports that the combined use of in situ interlayer hot forging and post-deposition heat treatment (PDHT) could alter typical coarse oriented microstructure Ni-based superalloy 625 obtained by arc plasma directed energy deposition (DED) to a fine non-oriented condition. In synchrotron X-ray diffraction electron backscatter showed high-temperature (1100 °C/ 1 h) PDHT induced significant recrystallization, leading grain refinement low texture index, while partially dissolving...
Wire and arc additive manufacturing of high‐strength low‐alloy steel is performed. The microstructures mechanical properties the samples are investigated correlated with process heat input. Continuous pulsed wave welding modes studied added material efficiencies determined. microstructural characterization microhardness test reveal that input effect more impactful when parts produced mode. Microstrain evolution phase fraction evaluated via synchrotron X‐ray diffraction. A higher percentage...
Defect detection in additive manufacturing (AM) is of paramount importance to improve the reliability products. Nondestructive testing not yet widely used for defect detection. The main challenges are a lack standards and methods, types location defects, complex geometry many parts. During selective laser melting (SLM), several defects can occur such as porosity, cracking, fusion. In this study, nondestructive tests were conducted highly shaped part AISI 316L stainless steel with real...
Additive manufacturing technologies are becoming more popular, as they allow the fabrication of specific parts with complex geometries not achievable by conventional manufacturing. In metal additive manufacturing, one most widely used is laser powder bed fusion. This work focuses on influence different processing parameters density AISI 316L stainless obtained through this technology. The article presents a review published works deposition steel using fusion to define an optimal range...
The typical as-built coarse and cube-oriented microstructure of Inconel® 625 parts fabricated via arc-based directed energy deposition (DED) induces anisotropic mechanical behavior, reducing the potential applications DEDed in critical components. In this sense, present work aimed to reduce grain size texture by applying an situ interlayer hot forging (HF) combined with post-deposition heat treatments (PDHT). produced samples were characterized through optical microscopy, scanning electron...
CuAl8 alloy finds applications in industrial components, where a good anti-corrosion and anti-wearing properties are required. The has medium strength toughness with an elongation to fracture at room temperature of about 40%. Additionally, it electrical conductivity, though lower than that pure Al or Cu. Despite these characteristics, additive manufacturing the was not yet reported. In this work, direct energy deposition-arc (DED-arc) without in-situ hot forging used determine microstructure...
Functionally Graded Materials (FGMs) can outperform their homogeneous counterparts. Advances in digitalization technologies, mainly additive manufacturing, have enabled the synthesis of materials with tailored properties and functionalities. Joining dissimilar metals to attain compositional grading is a relatively unexplored research area holds great promise for engineering applications. Metallurgical challenges may arise; thus, theoretical critical analysis presented this paper. A...
We present a viable prototype of simple mechanical ventilator intended as last resort to ventilate COVID-19 patients. The implements the pressure-controlled continuous mandatory ventilation mode (PC-CMV) with settable breathing rates, inspiration/expiration time ratios and FiO2 modulation. Although safe, design aims minimize use technical components those used are common in industry, so its construction may be possible times logistical shortage or disruption areas reduced access materials at...
Abstract Wire and Arc Additive Manufacturing (WAAM) is increasingly being used to produce complex non-traditional geometries that other technologies are not able create. Finishing operations, as machining, often required accomplish the components functionality. However, recent studies suggest several machining issues arise due lack of geometrical tolerances shapes manufactured parts, like chattering effects, appropriate work holding selection component alignment. This aimed evaluate if...