Introduction of nanoprecipitation into supersaturated CoCrFeNiMo0.5 alloy prepared by laser-powder bed fusion via microstructure tailoring to achieve excellent properties

Due to rapid solidification characteristic of additive manufacturing (AM) technology, it is considered as an effective method to prepare highly concentrated metals and alloys. Therefore, in this work, we successfully prepared CoCrFeNiMo0.5 high-entropy alloy (HEA) with a small amount of nano precipitated particles (30-50 nm) by utilizing the ultrahigh cooling rate characteristic of laser-powder bed fusion (L-PBF). The as-printed sample shows an excellent combination of strength and ductility, with the yield strength, ultimate tensile strength and fracture elongation determined as 886 MPa, 1110 MPa and 30.1%, respectively. In addition, after aging treatment, plenty of nano-sized Mo-rich σ phases were precipitated in the supersaturated FCC matrix, thereby further adjusting the mechanical properties of the alloy and expanding the range of applications.