Effect of the Metal Transfer Mode on the Symmetry of Bead Geometry in WAAM Aluminum

The symmetrical nature in the case of wall fabrication by wire arc additive manufacturing (WAAM) has been observed in the literature, but it has not been studied as a source of knowledge. This paper focuses on the comparative study of three drop transfer methods employing Gas Metal Arc Welding (GMAW) technology, one of the most reported for the manufacture of aluminum alloys. The transfer modes studied are the well-known pulsed GMAW, cold arc, and the newer pulsed AC. The novelty of the last transfer mode is the reversal of the polarity during the preparation phase of the substance for droplet deposition. This study compares the symmetry of zero beads to determine the best parameters and transfer modes for wire arc additive manufacturing of 5 series aluminum. The pulsed transfer modes show values of 0.6 for symmetry ratio, which makes them more interesting strategies than cold arc with a symmetry ratio of 0.5. Furthermore, the methodology proposed in this study can be extrapolated to other materials manufactured with this technology.The authors acknowledge the Basque Government for financing the HARIPLUS, HAZITEK 2019 program (ZL-2019/00352), and QUALYFAM project (kk-2020/00042)

Influence of Heat Input on the Formation of Laves Phases and Hot Cracking in Plasma Arc Welding (PAW) Additive Manufacturing of Inconel 718

Nickel-based alloys have had extensive immersion in the manufacturing world in recent decades, especially in high added value sectors such as the aeronautical sector. Inconel 718 is the most widespread in terms of implantation. Therefore, the interest in adapting the manufacture of this material to additive manufacturing technologies is a significant objective within the scientific community. Among these technologies for the manufacture of parts by material deposition, plasma arc welding (PAW) has advantages derived from its simplicity for automation and integration on the work floor with high deposition ratios. These characteristics make it very economically appetizing. However, given the tendency of this material to form precipitates in its microstructure, its manufacturing by additive methods is very challenging. In this article, three deposition conditions are analyzed in which the energy and deposition ratio used are varied, and two cooling strategies are studied. The interpass cooling strategy (ICS) in which a fixed time is expected between passes and controlled overlay strategy (COS) in which the temperature at which the next welding pass starts is controlled. This COS strategy turns out to be advantageous from the point of view of the manufacturing time, but the deposition conditions must be correctly defined to avoid the formation of Laves phases and hot cracking in the final workpiece.The authors acknowledge the Basque Government ELKARTEK 2019 program (KK-2019/00004) and HARIPLUS project, HAZITEK 2019 program (ZL-2019/00352) and to the European commission through EiT Manufacturing programme in DEDALUS project (reference ID 20094)

Three-dimensional finite element modelling of sheet metal forming for the manufacture of pipe components: symmetry considerations

The manufacture of parts by metal forming is a widespread technique in sectors such as oil and gas and automotives. It is therefore important to make a research effort to know the correct set of parameters that allow the manufacture of correct parts. This paper presents a process analysis by means of the finite element model. The use case presented in this paper is that of a 3-m diameter pipe component with a thickness of 22 mm. In this type of application, poor selection of process conditions can result in parts that are out of tolerance, both in dimensions and shape. A 3D finite element model is made, and the symmetry of the tube section generated in 2D is analysed. As a novelty, an analysis of the process correction as a function of the symmetrical deformation of the material in this case in the form of a pipe is carried out. The results show a correct fitting of the model and give guidelines for manufacturing.The authors acknowledge the funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 958303

Validation of the Mechanical Behavior of an Aeronautical Fixing Turret Produced by a Design for Additive Manufacturing (DfAM)

The design of parts in such critical sectors as the manufacturing of aeronautical parts is awaiting a paradigm shift due to the introduction of additive manufacturing technologies. The manufacture of parts designed by means of the design-oriented additive manufacturing methodology (DfAM) has acquired great relevance in recent years. One of the major gaps in the application of these technologies is the lack of studies on the mechanical behavior of parts manufactured using this methodology. This paper focuses on the manufacture of a turret for the clamping of parts for the aeronautical industry. The design of the lightened turret by means of geometry optimization, the manufacture of the turret in polylactic acid (PLA) and 5XXX series aluminum alloy by means of Wire Arc Additive Manufacturing (WAAM) technology and the analysis by means of finite element analysis (FEA) with its validation by means of a tensile test are presented. The behavior of the part manufactured with both materials is compared. The conclusion allows to establish which are the limitations of the part manufactured in PLA for its orientation to the final application, whose advantages are its lower weight and cost. This paper is novel as it presents a holistic view that covers the process in an integrated way from the design and manufacture to the behaviour of the component in useThis project has received funding from the ELKARTEK program of the Basque Government (Project VIRTUA3D, under Contract nº KK-2022/00025) and HAZITEK (Project ADDHOC, under Contract nº ZL-2022/00665)

Three-dimensional finite element modelling of sheet metal forming for the manufacture of pipe components: symmetry considerations

The manufacture of parts by metal forming is a widespread technique in sectors such as oil and gas and automotives. It is therefore important to make a research effort to know the correct set of parameters that allow the manufacture of correct parts. This paper presents a process analysis by means of the finite element model. The use case presented in this paper is that of a 3-m diameter pipe component with a thickness of 22 mm. In this type of application, poor selection of process conditions can result in parts that are out of tolerance, both in dimensions and shape. A 3D finite element model is made, and the symmetry of the tube section generated in 2D is analysed. As a novelty, an analysis of the process correction as a function of the symmetrical deformation of the material in this case in the form of a pipe is carried out. The results show a correct fitting of the model and give guidelines for manufacturing.The authors acknowledge the funding from the European Union's Horizon 2020 research and innovation programme under grant agreement No. 958303

High-Temperature Mechanical Properties of IN718 Alloy: Comparison of Additive Manufactured and Wrought Samples

Wire Arc Additive Manufacturing (WAAM) is one of the most appropriate additive manufacturing techniques for producing large-scale metal components with a high deposition rate and low cost. Recently, the manufacture of nickel-based alloy (IN718) using WAAM technology has received increased attention due to its wide application in industry. However, insufficient information is available on the mechanical properties of WAAM IN718 alloy, for example in high-temperature testing. In this paper, the mechanical properties of IN718 specimens manufactured by the WAAM technique have been investigated by tensile tests and hardness measurements. The specific comparison is also made with the wrought IN718 alloy, while the microstructure was assessed by scanning electron microscopy and X-ray diffraction analysis. Fractographic studies were carried out on the specimens to understand the fracture behavior. It was shown that the yield strength and hardness of WAAM IN718 alloy is higher than that of the wrought alloy IN718, while the ultimate tensile strength of the WAAM alloys is difficult to assess at lower temperatures. The microstructure analysis shows the presence of precipitates (laves phase) in WAAM IN718 alloy. Finally, the effect of precipitation on the mechanical properties of the WAAM IN718 alloy was discussed in detail.This project received funding from the European Union’s Marie Skłodowska–Curie Actions (MSCA) Innovative Training Networks (ITN) H2020-MSCA-ITN-2017 under the grant agreement No. 764979 and Basque Government QUALYFAM project, ELKARTEK 2020 program (KK-2020/00042) and HARIPLUS project, HAZITEK 2019 program (ZL-2019/00352)

Model for the Prediction of Deformations in the Manufacture of Thin-Walled Parts by Wire Arc Additive Manufacturing Technology

Gas Metal Arc Welding (GMAW) is a manufacturing technology included within the differentWire Arc Additive Manufacturing alternatives. These technologies have been generating great attention among scientists in recent decades. Its main qualities that make it highly productive with a large use of material with relatively inexpensive machine solutions make it a very advantageous technology. This paper covers the application of this technology for the manufacture of thin-walled parts. A finite element model is presented for estimating the deformations in this type of parts. This paper presents a simulation model that predicts temperatures with less than 5% error and deformations of the final part that, although quantitatively has errors of 20%, qualitatively allows to know the deformation modes of the part. Knowing the part areas subject to greater deformation may allow the future adaptation of deposition strategies or redesigns for their adaptation. These models are very useful both at a scientific and industrial level since when we find ourselves with a technology oriented to Near Net Shape (NNS) manufacturing where deformations are critical for obtaining the final part in a quality regime.This research was funded by the vice-counseling of technology, innovation and competitiveness of the Basque Government grant agreement kk-2019/00004 (PROCODA project) and the QUALYFAM project, through the ELKARTEK 2020 (KK-2020/00042) and the ADIFIX project funded by HAZITEK 2019 and 2020 (ZL-2019/00738, ZL-2020/00073) programs and the Spanish Government CDTI-Red Cervera Programme (EXP 00123730/IDI-20191162)

Review of Intermediate Strain Rate Testing Devices

Materials undergo various loading conditions during different manufacturing processes, including varying strain rates and temperatures. Research has shown that the deformation of metals and alloys during manufacturing processes such as metal forming, machining, and friction stir welding (FSW), can reach a strain rate ranging from 10−1 to 106 s−1. Hence, studying the flow behavior of materials at different strain rates is important to understanding the material response during manufacturing processes. Experimental data for a low strain rate of 103 s−1 are readily available by using traditional testing devices such as a servo-hydraulic testing machine and the split Hopkinson pressure bar method, respectively. However, for the intermediate strain rate (101 to 103 s−1), very few testing devices are available. Testing the intermediate strain rate requires a demanding test regime, in which researchers have expanded the use of special instruments. This review paper describes the development and evolution of the existing intermediate strain rate testing devices. They are divided based on the loading mechanism; it includes the high-speed servo-hydraulic testing machines, hybrid testing apparatus, the drop tower, and the flywheel machine. A general description of the testing device is systematically reviewed; which includes the working principles, some critical theories, technological innovation in load measurement techniques, components of the device, basic technical assumption, and measuring techniques. In addition, some research direction on future implementation and development of an intermediate strain rate apparatus is also discussed in detail.This project received funding from the European Union’s Marie Skłodowska–Curie Actions (MSCA) Innovative Training Networks (ITN) H2020-MSCA-ITN-2017 under the grant agreement No. 76497

Effect of Heat Treatment on the Microstructure and Hardness of Ni-Based Alloy 718 in a Variable Thickness Geometry Deposited by Powder Fed Directed Energy Deposition

Feature addition to existing parts is a trending application for Directed Energy Deposition (DED) and can be used to add complex geometry features to basic forged geometries with the aim to reduce and simplify the number of processing steps as machining and assembling. However, the mechanical properties of as-deposited Inconel 718 fabricated by Powder-fed Directed Energy Deposition (Powder-fed DED) are far lower than the relevant specifications, making it necessary to apply different heat treatment with the purpose of improving deposited material performance. In addition, the effects of heat treatments in both variable thickness deposited geometry and forge substrate have not been studied. In this study, the effect of heat treatment within the Aerospace Materials Specifications (AMS) for cast and wrought Inconel 718 on the microstructure and hardness of both the Ni-Based Alloy 718 deposited geometry and substrate are analyzed in different parts of the geometry. The microstructure of all samples (as-deposited and heat-treated) is analyzed by Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS), confirming the formation of aluminum oxides and titanium nitrides and carbonitrides in the deposited structure.This research was funded by the vice-counsel of technology, innovation and competitiveness of the Basque Government (Eusko Jaurlaritza) under the ELKARTEK Program, QUALYFAM and EDISON projects, grant number KK-2020/00042 and KK-2022/00070, respectively

Experimental characterization of material by means of shear testing at intermediate strain rate and elevated temperatures

Los capítulos 2 y 3 están sujetos a confidencialidad por el autor. 133 p.El doctorado forma parte del proyecto ENABLE (European Network for Alloys Behaviour Law Enhancement) que ha recibido financiación del programa de investigación e innovación Horizon 2020 de la Unión Europea bajo el acuerdo de subvención Marie Sklodowska-Curie N°764979. El trabajo también se ha desarrollado en el marco del laboratorio transfronterizo conjunto LTC ÆNIGME, entre la Universidad del País Vasco (UPV/EHU), la Universidad de Bordeaux (UBx) y Arts et Métiers Science et Technologie (ENSAM). El objetivo del doctorado es caracterizar experimentalmente el comportamiento a cizalla de una aleación de aluminio (AA7075-T6), en el rango de velocidad de deformación intermedia (101-103s-1) y temperatura elevada (hasta 0,7 veces la temperatura de fusión).La fabricación de componentes metálicos implica a menudo la deformación del material a velocidades de deformación de medias a altas y a temperaturas elevadas, especialmente en los procesos de conformación, mecanizado, soldadura por fricción (FSW), etc. Además, en muchos procesos de fabricación, la deformación dentro del material se genera por esfuerzos de cizallamiento y no por esfuerzos de tracción o compresión. Sin embargo, los dispositivos de ensayo mecánico existentes no son capaces de proporcionar un historial completo del comportamiento del material durante el proceso de fabricación en el rango de la velocidad de deformación y la temperatura.Los principales pasos tecnológicos y científicos para superar la preocupación:- Diseño y desarrollo de un nuevo banco de pruebas experimental para realizar el ensayo de cizallamiento a una velocidad de deformación intermedia.- La definición de ensayos termomecánicos capaces de reproducir las mismas solicitaciones que durante el mecanizado (velocidad de deformación media y deformación de rango medio), FSW (velocidad de deformación media, alta deformación), etc.- Proporcionar un comportamiento experimental detallado del material y realizar investigaciones microestructurales.Se desarrolla un nuevo dispositivo experimental de prueba de torsión basado en el principio de la rueda volante de inercia para reproducir localmente los niveles de tensión y las tasas de deformación que se encuentran en procesos como el mecanizado o el FSW. EnAbstractuna primera etapa, este dispositivo permite, mediante esfuerzos de torsión, alcanzar deformaciones a velocidades de deformación medias (en el rango de 102-103s-1). A continuación, se realizará una evolución para realizar ensayos de temperatura (hasta 0,7 veces la temperatura de fusión para las tres aleaciones estudiadas). La novedad de este equipo radica en los ensayos dinámicos en torsión que pueden realizarse bajo velocidades de deformación intermedias controlando la velocidad de carga. La deformación de la muestra se mide mediante una cámara de grabación de alta velocidad y la carga se mide mediante la técnica de la barra de Hopkinson. El nuevo banco de pruebas se implementa en la plataforma dinámica presente en el I2M, Burdeos, Francia.Tras la fabricación del dispositivo de prueba, se lleva a cabo la calibración de los diferentes componentes de medición para obtener resultados precisos de par y deformación. Por último, se realizan las pruebas preliminares. Una vez validado el banco de pruebas, se realizan ensayos a temperatura ambiente y a alta temperatura. Para ello, se adopta el diseño del experimento (DOE), con el fin de optimizar y organizar la campaña de ensayos. Los ensayos se realizan a diferentes velocidades de carga y temperaturas. También se realizan varias investigaciones microestructurales con el fin de identificar claramente los mecanismos que rigen la evolución de la respuesta plástica cubriendo un amplio rango de temperaturas, deformaciones y velocidades de deformación. Se estudia a fondo la caracterización mecánica y microestructural del material.Por último, se comparan las curvas de tensión de flujo obtenidas en el nuevo banco de ensayos de torsión a diferentes velocidades de deformación y a diferentes temperaturas con los modelos clásicos de material existentes que se utilizan habitualmente para la modelización del comportamiento constitutivo del AA7075-T6. Los parámetros de los modelos de material se determinan experimentalmente. La comparación con los resultados experimentales permite evaluar la adecuación de los modelos existentes y proponer una línea de base para la mejora del modelo existente o el desarrollo de un nuevo modelo de material