Investigating the laser metal deposition of Inconel 718 superalloy using the numerical and experimental methods

Abstract

In this research, a volume of fluid (VOF) model was developed to investigate the effect of laser deposition parameters on the geometry of molten pool and deposited layer in the Inconel 718 superalloy. For this purpose, the process parameters of laser power, laser beam diameter and scanning speed were considered to estimate the geometric characteristics of the molten pool and deposited layer. In the following, the laser deposition process of Inconel 718 superalloy was carried out experimentally to validate the results of simulation. It was observed that an increase in the laser power from 100 to 400 W resulted in an improvement in the length, width and depth of molten pool, while an increase in the values of laser beam diameter (from 1 to 2 mm) and scanning speed (from 2 to 10 mm s−1) was associated with a reduction in the length, width and depth of molten pool. From the results of both simulation and experiments, a reduction was observed in the wetting angle of deposited layer when the values of laser power and scanning speed increased up to 400 W and 10 mm s−1 respectively, while the increase of feeding rate from 48 to 62 mgr s−1 indicated an improvement in the wetting angle. It was also observed that the maximum penetration depth was obtained in the rear part of molten pool due to Marangoni convection currents that pushed the melt toward the end of molten pool. The comparison of the experimental results and those predicted by the VOF model indicated that the model is capable of predicting the shape of deposition layer with sensible error.

Sintering parameter optimization by inverse analysis in direct metal deposition of Inconel 718

“…As can be seen from Figure 6, the maximum measured temperature without powder injection is about 70°C and with powder injection is about 50°C. The low temperature in this small distance from the surface (2 mm) is due to the low dimensions of the molten pool, which is also reported in the numerical simulation results (Afshari et al, 2023c;Afshari et al, 2022b;Afshari et al, 2023a).…”

“…Therefore, the best choice is numerical simulation of the DMD process with a validated model. The designed model should consider mass, momentum and energy transfer relationships as well as physical phenomena during the additive manufacturing process to predict the behavior of the microstructure during solidification (Afshari et al, 2023b;Afshari et al, 2023c). Using this model, it is possible to predict the maximum pool temperature, fluid velocity distribution in the pool, molten pool boundary, solidification geometry, solidification microstructure, solidification volume change, residual stress, distortion and changes in some mechanical properties.…”

“…Therefore, the best choice is numerical simulation of the DMD process with a validated model. The designed model should consider mass, momentum and energy transfer relationships as well as physical phenomena during the additive manufacturing process to predict the behavior of the microstructure during solidification (Afshari et al. , 2023b; Afshari et al.…”

Evaluation of the Effect of Process Parameters on Mass Efficiency in Direct Metal Deposition of Inconel 718 with Response Surface Methodology

“…In these equations, the actual mass ow rate of the powder added to the pool is in mg/s, P is the laser power in watts, V is the scanning speed of the laser beam in mm/s, and F is the powder injection rate or the mass ow rate exiting the nozzle in mg/s. s is These relationships are used as inputs for numerical models and simulations in the part of the mass ow rate entering the part [4,5] As can be deduced from equations 3 and 4, laser power has the greatest effect on the percentage of powder absorption by the weld pool. This has also been reported in other similar studies [25].…”

“…The mass of material deposited on the surface per unit of time (real mass ow rate) and the ratio of the mass of powder added to the surface to the mass of powder exiting the nozzle (mass e ciency) are important parameters in additive manufacturing processes especially in direct metal deposition (DMD) and selective laser sintering (SLS) which determines the production speed of the part [1]. Also, for the simulation of additive manufacturing processes, it is necessary to determine the actual mass ow rate as the input of the simulation model [2][3][4][5]. Some articles use mass-energy balance equations.…”