Finite-element analysis and experimental validation of thermal residual stress and distortion in electron beam additive manufactured Ti-6Al-4V build plates

Cao, Jun; Gharghouri, Michael A.; Nash, Philip

doi:10.1016/j.jmatprotec.2016.06.032

Cited by 178 publications

(104 citation statements)

References 12 publications

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“…Prediction of the induced RS is one of the main motivations for developing process simulation methods, but the RS state is complex to determine as the thermal history is characterized by layer upon layer overlapping, which results in repeated partial heating, melting, and solidification [44]. The RS and distortions on AM processes are not well understood yet [45].…”

Section: Introduction Of Intermetallic Compounds and Metal Matrix Commentioning

confidence: 99%

“…Developing improved FEM and analytical models is crucial in order to facilitate the task of choosing the optimized process parameters, reducing the need of costly and time-consuming experimental works. Furthermore, such models may allow prediction of the microstructure evolution, RS, and part distortions [45]. Ideally, the models need to be accurate, high computationally efficient and intuitive; however, PBF-LB is a multi-physics complex problem to analyze [53].…”

Section: Introduction Of Intermetallic Compounds and Metal Matrix Commentioning

confidence: 99%

See 1 more Smart Citation

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

Barros

Silva

Gouveia

et al. 2019

Metals

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Residual stresses (RS) of great magnitude are usually present in parts produced by Laser Powder Bed Fusion (PBF-LB), mainly owing to the extreme temperature gradients and high cooling rates involved in the process. Those "hidden" stresses can be detrimental to a part's mechanical properties and fatigue life; therefore, it is crucial to know their magnitude and orientation. The hole-drilling strain-gage method was used to determine the RS magnitude and direction-depth profiles. Cuboid specimens in the as-built state, and after standard solution annealing and ageing heat treatment conditions, were prepared to study the RS evolution throughout the heat treatment stages. Measurements were performed on the top and lateral surfaces. In the as-built specimens, tensile stresses of~400 MPa on the top and above 600 MPa on the lateral surface were obtained. On the lateral surface, RS anisotropy was noticed, with the horizontally aligned stresses being three times lower than the vertically aligned. RS decreased markedly after the first heat treatment. On heat-treated specimens, magnitude oscillations were observed. By microstructure analysis, the presence of carbides was verified, which is a probable root for the oscillations. Furthermore, compressive stresses immediate to the surface were obtained in heat-treated specimens, which is not in agreement with the typical characteristics of parts fabricated by PBF-LB, i.e., tensile stresses at the surface and compressive stresses in the part's core.Diverse metals AM techniques exist, and the most adopted in the industry are Powder Bed Fusion (PBF) and Directed Energy Deposition (DED), as for the classification by the ISO/ASTM 52900 (2015) international standard. These two techniques use a laser or an electron beam as a high energy density source to selectively melt the material and build the parts [3][4][5][6][7]. Actually, different nomenclatures are used for the same process. Laser Powder Bed Fusion (PBF-LB) is also known as Selective Laser Melting (SLM), Direct Metal Laser Sintering (DMLS), and Laser Cusing [7,8,11], depending mostly on the AM systems supplier.Focusing on PBF-LB, a micro-size powder is spread in thin layers of 20 and 50 µm [3], and then a laser beam guided by a galvanometric mirror selectively melts the deposited material according to the CAD model. The parts are built progressively from bottom to top, also known as the building direction (vertical) [7,11]. The use of support structures is common, either to support down-facing surfaces or to prevent part distortion. Part distortion occurs due to the large residual stresses (RS) generated during material solidification layer-by-layer, owing to the extreme temperature gradients and high cooling rates [12].New feedstock materials dedicated to AM systems have been developed; thereby, new opportunities will arise in the near future of AM [13]. Stainless steel; tool steel; and Ni-, Al-, Ti-, Co-Cr-, and Cu-based alloys are just a few of the metallic materials currently available for AM [7,14,15]. Introduction of int...

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Section: Introduction Of Intermetallic Compounds and Metal Matrix Commentioning

confidence: 99%

Section: Introduction Of Intermetallic Compounds and Metal Matrix Commentioning

confidence: 99%

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

Barros

Silva

Gouveia

et al. 2019

Metals

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“…Cladding processing cell (1) is equipped with a control unit (2). Сell (1) consisting of 5-axis positioning system, optical head with water cooling and supply of protective gas and powder from the feeder (3) Sulzer Metco Twin 10 -C, as also industrial digital camera for positioning parts and monitoring the process.…”

Section: Materials and Equipmentmentioning

confidence: 99%

“…It is necessary to provide wide complex of researches and tests. Titanium alloys are used in the following additive technology: melting layer by layer powder by electron beam (EBM) [1,2] or laser (SLM, SLS methods) [3,4], feeding melted powder or wire by plasma arc [5,6] or laser (DMLD) [7,8]. We suggest using laser metal deposition technology for manufacturing of titanium parts.…”

Section: Introductionmentioning

confidence: 99%

Direct metal laser deposition of titanium powder Ti-6Al-4V

Bykovskiy

Petrovskiy

Sergeev

et al. 2017

J. Phys.: Conf. Ser.

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Abstract. The paper presents the results of mechanical properties study of the material produced by direct metal laser deposition of VT6 titanium powder. The properties were determined by the results of stretching at tensile testing machine, as well as compared with the properties of the same rolled material. These results show that obtained samples have properties on the level or even higher than that ones of the samples obtained from the rolled material in a certain range of technological regimes. IntroductionTitanium alloys have already well approved themselves in chemical, marine, aerospace industries. They are very strong, able to withstand heavy loads and have reduced mass. In addition, titanium alloys are used for manufacturing implants and prostheses. Tissues around such implants are not subjects to change. They are resistant to corrosion in aggressive environment of the human body, and oxide coating on their surface prevents the escape of the implant ions into the body. However, the manufacture of titanium parts and implants is strictly individual task, as it is a material, which is difficult to process. This fact significantly increases the cost of a product. There is a significant interest in using different additive technology for manufacturing titanium parts in recent times. It is necessary to provide wide complex of researches and tests. Titanium alloys are used in the following additive technology: melting layer by layer powder by electron beam (EBM) [1,2] or laser (SLM, SLS methods) [3,4], feeding melted powder or wire by plasma arc [5,6] or laser (DMLD) [7,8]. We suggest using laser metal deposition technology for manufacturing of titanium parts. This technology involves melting of metallic powder feeding through the nozzle coaxially with the radiation. When the nozzle moves along the surface, new metal layer will be formed after solidification. Thus, it is possible to produce parts of the desired shape. The research presents the results of the mechanical properties study of the samples obtained by laser metal deposition technology by different technological modes.

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“…The tensile stresses measured for this experiment were measured in the longitudinal direction and were found to be greater than 300MPa (Cao & Gharghouri, 2016). An analysis of residual stresses in WAAM Ti-6Al-4V components was completed by Martina et al Tensile residual stresses up to 500MPa were achieved.…”

Section: Stress Relievingmentioning

confidence: 73%

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti-6Al-4V Produced by Wire Arc Additive Manufacturing

Nicastro¹

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The following report investigates the effect of heat treatment on the microstructure and mechanical properties of Ti-6Al-4V produced by Wire Arc Additive Manufacturing (WAAM).WAAM has arisen as a relatively new and successful technology for the production of aeronautical and mechanical components in industry. As a novel concept however, there are many untouched areas of investigation that should be explored to gain a better understanding of the topic. Through this study, the benefits of the different heat treatments and hot isostatic pressing on Wire Arc Additive Manufactured components will be assessed to determine their

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Finite-element analysis and experimental validation of thermal residual stress and distortion in electron beam additive manufactured Ti-6Al-4V build plates

Cited by 178 publications

References 12 publications

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

Laser Powder Bed Fusion of Inconel 718: Residual Stress Analysis Before and After Heat Treatment

Direct metal laser deposition of titanium powder Ti-6Al-4V

Effect of Heat Treatment on the Microstructure and Mechanical Properties of Ti-6Al-4V Produced by Wire Arc Additive Manufacturing

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