Numerical Simulation and Experimental Research on Multi-Channel Laser Directional Energy Deposition of IN718

Abstract

In this paper, the deposition layer calculation model is proposed for laser-directed energy deposition (DED) with coaxial powder feeding by combining the powder feeding equation with the volume of fluid (VOF) method, and the single-channel IN718 forming process is simulated in real-time with moving boundary conditions in a fixed coordinate system and experimentally validated. Under single-layer single-channel deposition processing, the deposition height and width decreased by 57.1% and 21.6%, respectively, as the scanning speed increased from 8 mm/s to 14 mm/s. The calculated deposition height, width, and melt pool depth were in good agreement with the experimental results. Calculating the temperature field distribution of the single-layer double-channel deposition at an overlapping-rate of 30% yielded the temperature fluctuation pattern of the deposition at various lap moments. Under the influence of the thermal accumulation of the first deposition channel, the latent heat effect of the melt pool will cause the maximum surface temperature during overlap processing to be slightly lower than the maximum surface temperature during single channel processing; at the same time, under the influence of the high-temperature state of the overlap deposition channel during the scanning process, the first deposition channel will exhibit rewarming during the overlap scanning process. The deposition layer and temperature field of single-layer multi-channel laser deposition are modelled using this information. It has been proved that the model may be used to forecast deposition and temperature fields for intricate processing procedures. The study findings are significant for understanding the process mechanism of coaxial powder feeding laser-directed energy deposition in detail and optimizing the process.