Spatiotemporal variations of residual stresses during multi-track and multi-layer deposition for laser powder bed fusion of Ti-6Al-4V
TL;DR: In this paper, a 3D finite element model was developed to study the spatiotemporal variations of the temperature and the stresses during multi-track and multi-layer LPBF.
About: This article is published in Computational Materials Science.The article was published on 2021-07-01. It has received 15 citations till now. The article focuses on the topics: Residual stress & Stress (mechanics).
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TL;DR: In this paper, a comprehensive review based on the process-microstructure-properties relationship in precipitation-hardenable high-entropy alloys fabricated by 3D printing is provided.
44 citations
TL;DR: In this paper , the authors provide a comprehensive review of the application of wire arc additive manufacturing of aluminium alloys for the production of parts in the aerospace and automotive industries, their metallurgical characteristics, and mechanical properties have been reviewed and discussed in detail to identify the research gap and future research directions.
Abstract: Wire arc additive manufacturing (WAAM) is suitable for printing medium-to-large complex parts with structural integrity while reducing material wastage, and lead time, improving the quality and customized design for functional components. Aluminium alloys are one of the most commonly used metallic materials in manufacturing parts for aerospace and automotive applications due to their lightweight, excellent strength, and corrosion resistance properties. Aluminium alloys have been employed in the WAAM process to produce parts for the aerospace and automotive industries. In this paper, various research works associated with the application of WAAM of aluminium alloys for aerospace and automotive industries, their metallurgical characteristics, and mechanical properties have been reviewed and discussed in detail to identify the research gap and future research directions. This paper is patterned to provide a comprehensive review of WAAM of aluminium alloys for the production of parts in the aerospace and automotive industries. Abbreviations: AM: Additive manufacturing; Al: Aluminium; Bi: Bismuth; BIW: Body in white; CNC: Computer numerical machines; CMT: Cold metal transfer; CNN: Convolutional neural networks; CL: Curved layer; DE-GMAAM: Double-electrode gas metal arc additive manufacturing; DWAAM: Double wire arc additive manufacturing; DMD: Direct metal deposition; DMLS: Direct metal laser sintering; DED-arc: Directed energy deposition arc; 3D: Three-dimensional; EAC: Environmentally assisted cracking; EBM: Electron beam melting; FCI: Fatigue crack initiation; Fe: Iron; GTAW: Gas tungsten arc welding; GMAW: Gas metal arc welding; HE: Hydrogen embrittlement; HAZ: Heat-affected zone; HWAAM: Hot wire arc additive manufacturing; IISCC: Irradiation induced stress corrosion cracking; Li: Lithium; Mg: Magnesium; Mn: Manganese; Ni: Nickel; OL: Online cooling; Pb: Lead; PAW: Plasma arc welding; RS: Robotic system; SCC: Stress corrosion cracking; SLM: Selective laser melting; SCG: Short crack growth; SLC: Super light car; Si: Silicon; Ti: Titanium; Zr: Zirconium
24 citations
TL;DR: In this paper, a high-speed, high-resolution imaging technology and multi-laser powder bed fusion (ML-PBF) equipment was used to investigate the dual-beam laser-matter interaction at the overlap region.
Abstract: To meet the urgent demand of large-scale parts fabrication in aerospace and energy fields, laser powder bed fusion (LPBF) additive manufacturing is developing towards multi-laser powder bed fusion (ML-PBF). However, defects such as the surface quality degradation and lack of fusion are more prone to appear at the overlap region of the deposit printed by multiple laser beams, which is detrimental to the consistency and uniformity of parts formed using ML-PBF. Here, based on a high-speed, high-resolution imaging technology and our ML-PBF equipment, the dual-beam laser-matter interaction at the overlap region in ML-PBF was investigated. At the overlap region, the collision and interaction between two molten pools influences the flow pattern of the liquid metal, accompanied by the large-sized droplet spatter expelling out. Moreover, the collision and accumulation of the liquid metal and spatter are responsible for the formation of the surface and internal structure defects of overlap samples. Furthermore, we reveal multiple transitions of the dominant mechanisms of the spatter formation in ML-PBF, which can be interchanged from the vapor-induced recoil pressure dominant stage to the vapor-induced entrainment dominant stage. We also propose the growth rate of spatter number rs, which can be well correlated with the transient transition of spatter formation mechanism. This work is expected to provide the scientific basis for ML-PBF to achieve consistency and uniformity.
23 citations
TL;DR: In this paper, the authors evaluated the printability of a high strength aluminum alloy AA2024 for laser powder bed fusion (LPBF) with comparisons to the widely used AlSi10Mg.
Abstract: The rapid development of additive manufacturing requires a large number of printable metallic materials for various engineering applications. In this work, the printability of a high strength aluminum alloy AA2024 was evaluated for laser powder bed fusion (LPBF) with comparisons to the widely used AlSi10Mg. Strikingly different solidification cracking networks were generated when using diverse scanning strategies and overlap rates of adjacent tracks. Depending on the overlap rates, the crack propagation patterns transited from the longitudinal-dominant to the transverse-dominant. The lengths and propagation angles of the transverse zigzag cracks were strongly interdependent and both increased with the overlap rate of adjacent tracks. The characterization results implied that these diverse crack propagation patterns originated from the columnar grain structure, which were produced in the localized solidification conditions determined by the track-wisely moving molten pool. The characteristics of the thermal cycles and solidification conditions of AlSi10Mg and AA2024 were further examined using a comprehensive phenomenological model for a better understanding of the printability of AA2024. The results showed that AA2024 generated smaller molten pool and that AA2024 was more susceptible to lack of fusion defects given the same LPBF process conditions. Supported by the evaluated printability of AA2024, a comprehensive scheme targeting the printing of crack-free LPBF builds was proposed considering the heat input, the overlap rate, and the scanning strategies of the laser beam.
19 citations
TL;DR: In this paper , the influence of heat treatments on the evolution of MC- and M23C6-type carbides within a Haynes® 282 superalloy prepared by wire arc additive manufacturing (WAAM).
9 citations
References
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TL;DR: A review of the emerging research on additive manufacturing of metallic materials is provided in this article, which provides a comprehensive overview of the physical processes and the underlying science of metallurgical structure and properties of the deposited parts.
4,192 citations
TL;DR: The approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines, and provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting.
Abstract: Metal-based additive manufacturing, or three-dimensional (3D) printing, is a potentially disruptive technology across multiple industries, including the aerospace, biomedical and automotive industries. Building up metal components layer by layer increases design freedom and manufacturing flexibility, thereby enabling complex geometries, increased product customization and shorter time to market, while eliminating traditional economy-of-scale constraints. However, currently only a few alloys, the most relevant being AlSi10Mg, TiAl6V4, CoCr and Inconel 718, can be reliably printed; the vast majority of the more than 5,500 alloys in use today cannot be additively manufactured because the melting and solidification dynamics during the printing process lead to intolerable microstructures with large columnar grains and periodic cracks. Here we demonstrate that these issues can be resolved by introducing nanoparticles of nucleants that control solidification during additive manufacturing. We selected the nucleants on the basis of crystallographic information and assembled them onto 7075 and 6061 series aluminium alloy powders. After functionalization with the nucleants, we found that these high-strength aluminium alloys, which were previously incompatible with additive manufacturing, could be processed successfully using selective laser melting. Crack-free, equiaxed (that is, with grains roughly equal in length, width and height), fine-grained microstructures were achieved, resulting in material strengths comparable to that of wrought material. Our approach to metal-based additive manufacturing is applicable to a wide range of alloys and can be implemented using a range of additive machines. It thus provides a foundation for broad industrial applicability, including where electron-beam melting or directed-energy-deposition techniques are used instead of selective laser melting, and will enable additive manufacturing of other alloy systems, such as non-weldable nickel superalloys and intermetallics. Furthermore, this technology could be used in conventional processing such as in joining, casting and injection moulding, in which solidification cracking and hot tearing are also common issues.
1,670 citations
TL;DR: In this paper, the recent progress on Ti6Al4V fabricated by three mostly developed additive manufacturing techniques-directed energy deposition (DED), selective laser melting (SLM) and electron beam melting (EBM)-is thoroughly investigated and compared.
1,248 citations
Book•
01 Jun 1985
TL;DR: In this paper, the authors present a review of elementary mechanics of materials and their application in the field of energy engineering, including failure and failure criteria, stress, principal stresses, and strain energy.
Abstract: 1. Orientation, Review of Elementary Mechanics of Materials. 2. Stress, Principal Stresses, Strain Energy. 3. Failure and Failure Criteria. 4. Applications of Energy Methods. 5. Beams on an Elastic Foundation. 6. Curved Beams. 7. Elements of Theory of Elasticity. 8. Pressurized Cylinders and Spinning Disks. 9. Torsion. 10. Unsymmetric Bending and Shear Center. 11. Plasticity in Structural Members. Collapse Analysis. 12. Plate Bending. 13. Shells of Revolution with Axisymmetric Loads. 14. Buckling and Instability. References. Index.
1,200 citations
TL;DR: In this paper, the authors used an innovative simulation technique known as element birth and death, in modelling the three-dimensional temperature field in multiple layers in a powder bed, which indicated that the heated regions undergo rapid thermal cycles that could be associated with commensurate thermal stress cycles.
Abstract: Simulating the transient temperature field in additive layer manufacturing (ALM) processes has presented a challenge to many researchers in the field. The transient temperature history is vital for determining the thermal stress distribution and residual stress states in ALM-processed parts that utilise a moving laser heat source. The modelling of the problem involving multiple layers is equally of great importance because the thermal interactions of successive layers affect the temperature gradients, which govern the heat transfer and thermal stress development mechanisms. This paper uses an innovative simulation technique known as element birth and death, in modelling the three-dimensional temperature field in multiple layers in a powder bed. The results indicate that the heated regions undergo rapid thermal cycles that could be associated with commensurate thermal stress cycles. Deposition of successive layers and subsequent laser scanning produces temperature spikes in previous layers. The resultant effect is a steady temperature build-up in the lower layers as the number of layers increases.
583 citations