Improving the strength–ductility of laser powder bed fusion René 104 through high-density stacking faults induced by Sc and Y microalloying

Abstract

Improving the strength–ductility is crucial to the development of high-performance nickel-based superalloys fabricated via additive manufacturing (AM). In this study, Sc and Y microalloying is used to regulate the microstructure and improve the strength–ductility of René 104 supealloy (René 104ScY). The results suggest the formation of high-density stacking faults (SFs), Lomer–Cottrell locks, and nano-Al3(Sc,Y) phases in the René 104ScY matrix. The cellular/columnar structures are refined, the number of equiaxial grains increases, and the number of columnar grains and their aspect ratio decrease in René 104ScY. The synergistic effect of multiple strengthening mechanisms, including that formed by SFs, improves the strength and ductility of René 104ScY fabricated via laser powder bed fusion. The yield strength, tensile strength, and elongation of René 104ScY are 1059 ± 15 MPa, 1405 ± 10 MPa, and 28.8 % ± 0.6 %, respectively. This study provides a novel approach for developing high-performance nickel-based superalloys using AM.