Evolution of Melt Pool and Porosity During Laser Powder Bed Fusion of Ti6Al4V Alloy: Numerical Modelling and Experimental Validation

Ransenigo, Chiara; Tocci, Marialaura; Palo, Filippo; Ginestra, Paola; Ceretti, Elisabetta; Gelfi, Marcello; Pola, Annalisa

doi:10.1007/s40516-022-00185-3

Cited by 10 publications

(4 citation statements)

References 43 publications

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“…These pores are usually spherical in shape and smaller in size (<100 µm) when compared to the other two kinds of internal defects discussed above [ 225 ]. Gas pores are known to occur during the evolution of the melt pool, when it is largely unstable and gas from the environment gets entrapped [ 226 ]. It should be noted that gas defects are more likely to occur when the density of the Ti6Al4V powder is low before the 3D-printing process starts [ 206 , 227 ].…”

Section: Microstructural Imperfections In Slm-built Ti6al4v Constructsmentioning

confidence: 99%

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

Hijazi,

Dixon,

Armstrong

et al. 2023

Materials

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In recent years, the field of mandibular reconstruction has made great strides in terms of hardware innovations and their clinical applications. There has been considerable interest in using computer-aided design, finite element modelling, and additive manufacturing techniques to build patient-specific surgical implants. Moreover, lattice implants can mimic mandibular bone’s mechanical and structural properties. This article reviews current approaches for mandibular reconstruction, their applications, and their drawbacks. Then, we discuss the potential of mandibular devices with lattice structures, their development and applications, and the challenges for their use in clinical settings.

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Section: Microstructural Imperfections In Slm-built Ti6al4v Constructsmentioning

confidence: 99%

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

Hijazi,

Dixon,

Armstrong

et al. 2023

Materials

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“…Meanwhile, Lu Wang et al [ 85 ] used a coupled multi-physical field model including heat transfer, liquid flow, metal vaporization, margin effect, and Darcy’s law for numerical simulation, mainly simulating the velocity field and temperature field of the melt pool, etc., while using high-speed X-ray imaging for experimental verification, and found that the uneven distribution of recoil pressure on the surface of the keyhole increases the formation of keyhole pores; in addition, different process parameters also affect the formation of keyholes, while low ambient pressure can reduce or even eliminate the formation of keyhole pores, and the instability of the keyhole leads to the formation process of pores, as shown in Figure 11 . In addition to the numerical simulation analyses of the melt pool by the above scholars, other scholars have also conducted related studies [ 86 , 87 , 88 , 89 , 90 , 91 , 92 , 93 ], where scholars have mainly focused on the process of keyhole generation, the influence of process parameters and processing atmosphere on the melt pool morphology, and the relationship between the unstable state of the melt pool and part defects. At the same time, a multi-physics field coupling model was established to simulate the process of laser and metal powder interaction in a more realistic way.…”

Section: Mechanism Of Metal Evaporation In the Lpbf Processmentioning

confidence: 99%

Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion

et al. 2023

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Laser powder bed fusion (LPBF) is of great importance for the visual measurement and analysis of the metallization process, which is the process of solid, liquid, and gas phase transformations of metal powders under high-energy laser irradiation due to the low boiling point/high saturated vapor pressure. Since the evaporation of metals involves the interaction of driving forces such as vapor back pressure, surface tension, and gravity, the movement of the melt pool is not stable. At the same time, it also produces vaporization products such as vapor plumes and sprays, which cause defects such as bubbles, porosity, lack of fusion, inclusions, etc., during the manufacturing process of the parts, affecting the performance and manufacturing quality of the parts. More and more researchers are using imaging technologies, such as high-speed X-ray, high-speed visible light cameras, and high-speed schlieren imaging, to perform noncontact visual measurements and analyses of the melt pool, vapor plume, and spatter during the metal evaporation process, and the results show that the metal evaporation process can be suppressed by optimizing the process parameters and changing the processing atmosphere, thereby reducing part defects and improving part performance and built part quality. This paper reviews the research on metal evaporation mechanisms and visual measurement methods of metal evaporation, then discusses the measures of metal evaporation, and finally summarizes and prospects the future research hotspots of LPBF technology, according to the existing scholars’ research on numerical simulation analysis and visual measurement methods of the metal evaporation process.

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“…), or the anisotropy [7] in material properties. Thermomechanical simulation [8,9], and inherent strain approach [10,11] are two types of finite element (FE)-based simulation techniques frequently used for predicting properties of additively manufactured components ranging from melt pool prediction [12][13][14] to final residual stresses [15] and component distortions. Thermomechanical simulation is a more systematic and sequential approach in which the first step thermal analysis (TA) yields a transient temperature field, which is used as the thermal load to drive the subsequent mechanical analysis (MA) step.…”

Section: Introductionmentioning

confidence: 99%

Prediction and validation of melt pool dimensions and geometric distortions of additively manufactured AlSi10Mg

Ullah

Lian

Akmal

et al. 2023

Int J Adv Manuf Technol

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A finite element–based thermomechanical modeling approach is developed in this study to provide a prediction of the mesoscale melt pool behavior and part-scale properties for AlSi10Mg alloy. On the mesoscale, the widely adopted Goldak heat source model is used to predict melt pool formed by laser during powder bed fusion process. This requires the determination of certain parameters as they control temperature distribution and, hence, melt pool boundaries. A systematic parametric approach is proposed to determine parameters, i.e., absorption coefficient and transient temperature evolution. The simulation results are compared in terms of morphology of melt pool with the literature results. Considering the part-scale domain, there is increasing demand for predicting geometric distortions and analyzing underlying residual stresses, which are highly influenced by the mesh size and initial temperature setup. This study aims to propose a strategy for evaluating the correlation between the mesh size and the initial temperature to provide correct residual stresses when increasing the scale of the model for efficiency. The outcomes revealed that the predicted melt pool error produced by optimal Goldak function parameters is between 5 and 12%. On the part-scale, the finite element model is less sensitive to mesh size for distortion prediction, and layer-lumping can be used to increase the speed of simulation. The effect of large time increments and layer lumping can be compensated by appropriate initial temperature value for AlSi10Mg. The study aids practitioners and researchers to establish and validate design for additive manufacturing within the scope of desired part quality metrics.

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Evolution of Melt Pool and Porosity During Laser Powder Bed Fusion of Ti6Al4V Alloy: Numerical Modelling and Experimental Validation

Cited by 10 publications

References 43 publications

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

Titanium Alloy Implants with Lattice Structures for Mandibular Reconstruction

Review of Visual Measurement Methods for Metal Vaporization Processes in Laser Powder Bed Fusion

Prediction and validation of melt pool dimensions and geometric distortions of additively manufactured AlSi10Mg

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