In-situ monitoring plume, spattering behavior and revealing their relationship with melt flow in laser powder bed fusion of nickel-based superalloy

Abstract

Laser powder bed fusion (LPBF) is a highly dynamic and complex physical process, and single-track defects tend to accumulate into non-negligible internal defects of parts. The nickel-based superalloy single track was fabricated by LPBF, and its plume and spattering behavior were monitored in situ and recorded in real time based on image recognition and tracking in this study. The relationship among laser energy density, melt flow, plume and spattering behavior during LPBF was discussed. Volumetric energy density had limitations as a design parameter for LPBF. However, we found that plume and spattering behavior can be used as real-time design parameters for the processing of LPBF parts and implemented the initial velocity statistics for LPBF single-track spattering based on the centroid extraction algorithm. The influence of melt flow evolution paths on the spattering and plume behavior in three different melting modes was revealed, and a shift in plume behavior was found in the overlap region of the additive substrate. This study provides a new method for obtaining statistics of spattering-related physical quantities in the melting mode, which is beneficial for the development of processing methods to mitigate the instability of the LPBF process.