Wire + Arc Additive Manufacturing Williams, S. W.; Martina, F.; Addison, A. C. ...
Materials science and technology,
05/2016, Volume:
32, Issue:
7
Journal Article
Peer reviewed
Open access
Depositing large components (>10 kg) in titanium, aluminium, steel and other metals is possible using Wire + Arc Additive Manufacturing. This technology adopts arc welding tools and wire as feedstock ...for additive manufacturing purposes. High deposition rates, low material and equipment costs, and good structural integrity make Wire+Arc Additive Manufacturing a suitable candidate for replacing the current method of manufacturing from solid billets or large forgings, especially with regards to low and medium complexity parts. A variety of components have been successfully manufactured with this process, including Ti-6Al-4V spars and landing gear assemblies, aluminium wing ribs, steel wind tunnel models and cones. Strategies on how to manage residual stress, improve mechanical properties and eliminate defects such as porosity are suggested. Finally, the benefits of non-destructive testing, online monitoring and in situ machining are discussed.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Nowadays, there is a great manufacturing trend in producing higher quality net-shape components of challenging geometries. One of the major challenges faced by additive manufacturing (AM) is the ...residual stresses generated during AM part fabrication often leading to unacceptable distortions and degradation of mechanical properties. Therefore, gaining insight into residual strain/stress distribution is essential for ensuring acceptable quality and performance of high-tech AM parts. This research is aimed at comparing microstructure and residual stress built-up in Ti–6Al–4V AM components produced by Wire+Arc Additive Manufacturing (WAAM) and by laser cladding process (CLAD).
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•The highest residual stress values are in longitudinal (deposition) direction•The maximum stress is observed in between baseplate and the deposited wall•CLAD sample show lower residual stress than WAAM sample•Both specimens exhibit columnar grains with finer wavy morphology in CLAD•Compressive stress is observed in different regions depending on the process
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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Due to the feasibility of economically producing large-scale metal components with relatively high deposition rates, significant progress has been made in the understanding of the ...Wire Arc Additive Manufacturing (WAAM) process, as well as the microstructure and mechanical properties of the fabricated components. As WAAM has evolved, a wide range of materials have become associated with the process and its applications.
This article reviews the emerging research on WAAM techniques and the commonly used metallic feedstock materials, and also provides a comprehensive over view of the metallurgical and material properties of the deposited parts. Common defects produced in WAAM components using different alloys are described, including deformation, porosity, and cracking. Methods for improving the fabrication quality of the additively manufactured components are discussed, taking into account the requirements of the various alloys. This paper concludes that the wide application of WAAM still presents many challenges, and these may need to be addressed in specific ways for different materials in order to achieve an operational system in an acceptable time frame. The integration of materials and manufacturing process to produce defect-free and structurally-sound deposited parts remains a crucial effort into the future.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Herein, the feasibility of the gas tungsten arc welding‐based wire + arc additive manufacturing process for fabricating thin wall structures of niobium‐1 wt% zirconium (NbZr1) alloy is investigated. ...Three different heat input conditions (low, medium, and high) have been selected for fabricating it. The microstructure is characterized by using optical microscopy, scanning electron microscopy, X‐ray diffraction, energy‐dispersive spectroscopy, and electron backscattered diffraction (EBSD). The microstructure shows the columnar dendritic structure elongated in the build direction. No cracks or porosity are observed in the structure. Average Vickers hardness for low, medium, and high heat input conditions are 146.6, 162.1, and 163.5 HV, respectively. There is an increasing trend of microhardness value along the deposition height, which can be attributed to the difference in secondary dendritic arm spacing and the formation of precipitates. The tensile strength of the specimen is comparable to the conventional and additively manufactured structures. EBSD analysis confirms that possible subgrains are responsible for good mechanical properties at room temperature. In the majority of the tensile samples, the failure mechanism has been identified as a ductile fracture. The mechanical characteristics fluctuate with locations in each of the thin walls, suggesting anisotropy in the deposits.
Herein, wire + arc additive manufacturing process has been successfully implemented to fabricate refractory NbZr1 thin wall structure without any defects. Microstructure consists of a columnar dendritic structure along the build direction. Precipitates are formed in the interdendritic regions. Microhardness is higher compared to the conventional NbZr1 alloy. Tensile strength shows a good combination of strength and ductility.
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FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
Wire and Arc Additive Manufacturing (WAAM) is a metal 3D printing technique based on robotic welding. This technique yields potential in decreasing material consumption due to its high material ...efficiency and freedom of shape. Empirical measurements of WAAM, using a deposition rate of 1 kg/h, were performed on site of MX3D. The measured power consumption per kg stainless steel is 2.72 kW, of which 1.74 is consumed by the welder, 0.44 by the robotic arm, and 0.54 by the ventilation. The material loss was 1.1%. A 98% argon 2% CO2 welding gas was used with a flow of 12 l/min.
A cradle-to-gate Life Cycle Assessment (LCA) was performed. To give this assessment context, green sand casting and CNC milling were additionally assessed, through literature and databases. The purpose of this study is to develop insight into the environmental impact of WAAM. Results indicate that, in terms of total ReCiPe endpoints, the environmental impact of producing a kg of stainless steel 308 l product using WAAM is comparable to green sand casting. It equals CNC milling with a material utilization fraction of 0.75. Stainless steel is the main cause of environmental damage in all three techniques, emphasizing the importance of WAAM's mass reduction potential. When environmentally comparing the three techniques for fulfilling a certain function, optimized designs should be introduced for each manufacturing technique. Results can vary significantly based on product shape, function, materials, and process settings.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Additive manufacturing (AM) technology, in other words “layered manufacturing” or “3D printer technology” has been developing rapidly in recent years. Unlike the traditional manufacturing method ...(TM), the working principle of AM technology is to create layer-based production by deposition the layers on top of each other. Owing to its advantages such as material saving, lower cost, the ability to produce parts without the need for molds and the design flexibility in complex shaped parts, it has brought a breath of fresh air to the areas where it is used primarily medical, aerospace and automotive. However, the parts produced by AM method have dimensional limitations. According to recent studies, in order to eliminate this problem, metal materials produced with AM can be combined with commonly used by different welding methods so that large parts can be obtained. In this study, these welding methods are explained and recent researches are examined. AM technology and methods are introduced. The usage areas of the method are described. In addition, the welding parameters and the effects of this new method on the mechanical properties and microstructures are investigated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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•Mechanical properties of nickel-aluminum bronze/steel composite structures are superior to those of cast alloys.•The Fe3Al-based metallurgical layer can retard the failure of the ...composite structure.•The composite structure with two-sided deposition has better performance than single-sided deposition.
To explore whether a copper‐steel composite structure can replace cast nickel‐aluminum bronze (NAB), the microstructure and mechanical properties of an arc deposited NAB/steel composite structure were systematically studied. The results demonstrate that in the composite structure, the precipitation of the rosette‐like κI phase was inhibited, and the sizes of the α‐Cu and κ phases were finer than those of the as‐cast NAB. The texture density of the NAB layer was lower than that of as‐cast NAB. The metallurgical layer dominated by Fe3Al formed at the copper‐steel interface improved the strength of the composite structure. Compared with as‐cast NAB, the yield strength and hardness of the composite structure increased by 51% and 30%. The Young's moduli of the α‐Cu and β phases were higher than those of the as‐cast NAB. The tensile cracks of the alloys were distributed around the κ phase and in the β phases. In the composite structure, the copper‐layer cracked first and then extended to the copper‐steel interface along with the β phase. Finally, the interface failed, and the copper‐steel peeled off. In the tensile specimen, the κ phase was surrounded by dislocations and a large number of stacking faults and twins were generated.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Additively manufactured intersections have the theoretical risk to contain hydrostatic tensile residual stresses, which eventually cannot be thermally stress relieved. The stresses in Ti-6Al-4V ...wire + arc additively manufactured (WAAM) intersections are lower compared to single pass walls and stresses in continuous walls are larger compared to discontinuous walls with otherwise identical geometry. Thermal stress relief was found to virtually eliminate them.
Inter-pass rolling can yield the desired grain refinement, without having any noteworthy influence on the development of residual stresses. The strain measurement itself by neutron diffraction is facilitated by the refined microstructure, because the otherwise textured microstructure produces anisotropic peak intensity, not allowing Pawley refinement. Without rolling, the 101¯1 and 101¯3 family of hcp planes are the only ones that diffract consistently in the three principal directions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
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•Implementation and exploitation of a novel anisotropic Voronoi algorithm.•Generation of microstructures with spatially varying grain growth directions.•An ellipsoidal growth field ...closely mimics underlying solidification proces.•Extraction of grains in a grain-conforming and non-grain-conforming manner.•Two demonstration cases show a pronounced correspondence to input data.
In this paper, a novel anisotropic Voronoi algorithm is presented, along with its implementation and two application cases. In contrast to standard Voronoi tessellations, the proposed algorithm takes into account preferred growth directions, aspect ratios and areas of individual grains. Therefore, an elliptical growth field, which is defined on a per grain basis, is adopted which specifies the time a single grain seed point needs to grow to a specific point in the domain of interest. Grains can be extracted in a grain-conforming or non-grain-conforming manner. The latter case is applicable to simulations in which a predetermined mesh is used, e.g. voxel-mesh based simulations. The extraction can then be done in a straightforward manner. For the former case, a more elaborate extraction algorithm is presented. Finally, the characteristics of the resulting microstructural geometries of two application cases (wire + arc additively manufactured and cast metal microstructure) are studied. A pronounced correspondence with the experimental grain morphology is obtained. This algorithm is highly versatile for generating polycrystalline (metal) microstructures, especially since it closely mimics the underlying solidification process. However, it is more generally applicable to generate an anisotropic tessellation with spatially varying preferential growth directions.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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