A systematic investigation of the effects of process parameters on heat and fluid flow and metallurgical conditions during laser-based powder bed fusion of Ti6Al4V alloy

Bayat, Mohamad; Mohanty, Sankhya; Hattel, Jesper Henri

doi:10.1016/j.ijheatmasstransfer.2019.05.017

Cited by 74 publications

(31 citation statements)

References 60 publications

(87 reference statements)

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“…The values adopted for the described thermophysical properties and simulated process parameters are presented in Table 1. The fluid flow during melting has a great influence on the heat dissipation physics and, consequently, on the maximum temperatures achieved during the process [14]. However, in order to maintain the computational time low, the fluid flow is not directly considered.…”

Section: Figure 1 Schematic Drawing Of the Boundary Conditions For Thmentioning

confidence: 99%

Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties

Solheid

Mohanty

Bayat

et al. 2020

Journal of Laser Applications

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Laser polishing of metals consists of irradiating the part's surface with a laser beam, thus generating a molten layer that is redistributed and resolidified to create a surface with reduced roughness. However, the process is also characterized by an instantaneously formation of heat-affected zones with consequent microstructural changes that influences the mechanical properties. In order to understand the microstructural evolution during laser polishing of Ti-6Al-4V laserbased powder bed fusion samples, a thermal model is applied in the current study to predict the dimensions of the melted zones and the heat-affected areas. Furthermore, the results obtained through the simulations are discussed and compared to the experimental data, thereby establishing the validity of the process models. Finally, the experimental studies also include the evaluation of the material hardness and residual stresses after laser polishing.

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Section: Figure 1 Schematic Drawing Of the Boundary Conditions For Thmentioning

confidence: 99%

Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties

Solheid

Mohanty

Bayat

et al. 2020

Journal of Laser Applications

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“…The energy equation that was employed in the thermal modelling for the PBF-EB process is [ 10 , 26 ]:

where

is for density,

for specific heat capacity, T for temperature, t for time, L for latent heat of fusion, and

for heat flux. The liquid fraction f is assumed to be a linear function of temperature [ 27 ] as:

where

and

are the solidus and liquidus temperature, respectively.…”

Section: Methodsmentioning

confidence: 99%

Material Characterisation and Computational Thermal Modelling of Electron Beam Powder Bed Fusion Additive Manufacturing of Ti2448 Titanium Alloy

Wang

Zhang

et al. 2021

Materials

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Ti-24Nb-4Zr-8Sn (Ti2448) is a metastable β-type titanium alloy developed for biomedical applications. In this work, cylindrical samples of Ti2448 alloy have been successfully manufactured by using the electron beam powder bed fusion (PBF-EB) technique. The thermal history and microstructure of manufactured samples are characterised using computational and experimental methods. To analyse the influence of thermal history on the microstructure of materials, the thermal process of PBF-EB has been computationally predicted using the layer-by-layer modelling method. The microstructure of the Ti2448 alloy mainly includes β phase and a small amount of α″ phase. By comparing the experimental results of material microstructure with the computational modelling results of material thermal history, it can be seen that aging time and aging temperature lead to the variation of α″ phase content in manufactured samples. The computational modelling proves to be an effective tool that can help experimentalists to understand the influence of macroscopic processes on material microstructural evolution and hence potentially optimise the process parameters of PBF-EB to eliminate or otherwise modify such microstructural gradients.

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“…In this simulation, f is 1.7 and ƞ is 0.2. Also, a telescopic method was used for applying volumetric heating since the laser can penetrate the metal powders [43].…”

Section: Simulation Methodsmentioning

confidence: 99%

Local Thermal Rates and Gradients in Laser Powder Bed Fusion Metal Additive Manufacturing Method: Computer Simulation

Hosseinzadeh¹

2021

Preprint

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The powder bed fusion (PBF) metal additive manufacturing (AM) method uses an energy source like a laser to melt the metal powders. The laser can locally melt the metal powders and creates a solid structure as it moves. The complexity of the heat distribution in laser PBF metal AM is one of the main features that need to be accurately addressed and understood to design and manage an optimized printing process. In this research, the dependency of local thermal rates and gradients on print after solidification (in the heat-affected zone) was numerically simulated and studied to provide information for designing the print process. The simulation results were validated by independent experimental results. The simulation shows that the local thermal rates are higher at higher laser power and scan speed. Also, the local thermal gradients increase if the laser power increases. The effect of scan speed on the thermal gradients is opposite during heating versus cooling times. Increasing the scan speed increases the local thermal gradients in the cooling times and decreases the local thermal gradients during the heating. In addition, these simulation results could be used in artificial intelligence (AI) and machine learning for developing digital additive manufacturing.

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A systematic investigation of the effects of process parameters on heat and fluid flow and metallurgical conditions during laser-based powder bed fusion of Ti6Al4V alloy

Cited by 74 publications

References 60 publications

Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties

Laser polishing of additively manufactured Ti-6Al-4V: Microstructure evolution and material properties

Material Characterisation and Computational Thermal Modelling of Electron Beam Powder Bed Fusion Additive Manufacturing of Ti2448 Titanium Alloy

Local Thermal Rates and Gradients in Laser Powder Bed Fusion Metal Additive Manufacturing Method: Computer Simulation

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