Optimization of process parameters in laser beam powder bed fusion using surface texture and density of Inconel 718

Abstract

This study aims to optimize the process parameters for PBF-LB of Inconel 718 using the surface texture and density of the as-built specimen to fabricate high-quality products. In order to achieve this aim, the melting and solidification phenomena of the melt pool were examined using a high-speed camera, and the process map of laser power and scan speed was constructed by evaluating the surface texture and density of the as-built specimen to optimize the process parameters. In addition, the mechanical properties of the as-built specimens fabricated at the optimum process parameter derived from the process map were examined. Consequently, it was found that the optimum process parameter should be determined by consideration of the melting and solidification phenomena because the phenomena such as spattering and instability of the melt pool change with the process parameters. It was also found that the morphology of the track is affected by the spot size of the laser beam. It was revealed that the similarity of the process maps evaluated by surface texture and density of the specimens results in the correlation between the surface texture and the density. The optimum laser power and scan speed can be determined using the process maps evaluated by the surface texture and density of the specimens. The as-built specimen fabricated at the optimum process parameter showed anisotropic tensile behavior, and the tensile strength of the transverse specimen was higher than that of the longitudinal specimen. The tensile properties of the as-built specimen fabricated in this work were similar to those of the as-built specimen reported by the other works.

In-situ process monitoring and statistical quantification of powder bed forming and build processes in laser powder bed fusion additive manufacturing

“…These results may be because of the difference of melting behavior, as stated in Section 2.4. In our previous study [40] and Fig. 3, the surface texture of the process window (regime II) showed evenness due to almost uniform tracks because the melt pool is stable.…”

“…Additionally, the authors [40] revealed that the rougher is the surface texture of the solidi ed part, the lower is the density of the manufactured parts and the greater is the number of internal defects. As presented in Fig.…”

レーザ金属積層造形技術に関する基礎的研究と応用技術の開発

“…6 The representative melting and solidification behavior observed by high-speed camera at various fabrication conditions. 16) Fig. 4 SEM images of fresh and recycled AlSi10Mg powders (×500).…”

“…9 The schematic density-based process map between laser power and scan speed including surface texture images. 16) 「粉体および粉末冶金」Advanced Publication by J-STAGE…”