Deciphering Laves phase-induced failure and the strength-ductility synergy mechanism via in situ deformation for high-deposition-rate laser directed energy deposited Inconel 718 alloy

Herein, in-situ experiment is conducted to investigate the real-time deformation behavior of Laves phase and its effect on the failure process of HDR-LDED processed Inconel 718 alloy in this work. Taking the long-striped and granular Laves phases as the research objects respectively, the occurrence sequence of fragmentation and debonding of Laves phase was clarified for the first time. Furtherly, the interactions about the Laves phases-matrix and Laves phase-dislocations were analyzed with the progress of the loading, respectively. Finally, the essential influence mechanism of Laves phase on the strength and ductility of Inconel 718 alloy was profoundly revealed. The findings can offer the valuable theoretical insights for a comprehensive understanding of the failure process of Inconel 718 fabricated by HDR-LDED and the further promotion of its mechanical properties.