Microstructure, mechanical properties and corrosion resistance of laser direct energy deposited AlMo_0.25FeCoCrNi_2.1 high-entropy alloy: adjusted by annealing heat treatment

ABSTRACT

A novel AlMo_0.25FeCoCrNi_2.1 high-entropy alloy (HEA) was additively manufactured using laser direct energy deposition (LDED) process. The microstructure, mechanical properties and corrosion resistance of the prepared alloy were investigated and adjusted by annealing heat treatment. The results showed that inadequate melting and diffusion of Mo powders cause the nonuniform Mo concentration and finally result in the microstructure diversity in the banded layer. Fine lamellar eutectic structures composed of Mo-rich σ phase and body-centered cubic (BCC) phase form within Mo supersaturated FCC phases. The annealing heat treatment promotes the precipitation and coarsening of needle-like B2 phases within the incipient FCC phases and granular σ phases at phase boundaries between FCC and BCC/B2, synergistically improving the toughness of this alloy with slight deterioration of ultimate tensile strength. The corrosion resistance of the alloy is notably improved by a 2-hour annealing heat treatment. These results contribute to rapidly designing/manufacturing/adjusting novel HEAs by LDED process.

KEYWORDS:

• Annealing heat treatment
• microstructure
• mechanical properties
• corrosion resistance
• laser directed energy deposition
• high-entropy alloys

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

The authors declare that all data supporting the findings of this study are available within the paper.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China [Grant Nos. 51905253, 51975136], the National Natural Science Foundation of Guangdong Province [Grant Nos. 2024A1515010525, 2023A1515011723] the Science and Technology Projects of Guangzhou [Grant Nos. 2023A04J1007, 2023A03J0077].