Physics-based crack formation model for Rene 80 in laser blown directed energy deposition: Theory and experiment

Hot cracking prevents the additive manufacturing of a range of high-strength and temperature alloys. This work presents a physics-driven method for avoiding crack formation in the crack-susceptible nickel-based superalloy Rene & PRIME; 80 built using laser blown-powder directed energy deposition (DED-LB/M). A hierarchal model that links process parameters, thermal features, and crack formation is proposed. The model uses a multi-source Rosenthal model calibrated against process monitoring to provide thermal features as an input to a simplified crack formation criterion based on the Rappaz-Drezet-Gremaud model. The results of the hierarchal model are developed and tested on single-pass walls built with a range of process parameters. The model matches the observed crack formation trend. The concepts are then applied for contour and hatch walls, and results suggest that this approach may be geometrically generalizable.