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Herein, a combination of cold rolling (CR) and annealing treatment is used to investigate the evolution of the microstructure and mechanical properties of CoFeNiMnV high‐entropy alloys (HEAs) fabricated by powder plasma arc additive manufacturing (PPA‐AM). The deposited CoFeNiMnV HEAs exhibit a face‐centered cubic (FCC) structure with a small amount of σ phase precipitation. After 50% CR, the microstructure of CoFeNiMnV HEAs is severely deformed along the rolling direction, and the grain size is obviously refined. Therefore, the hardness and strength of the alloy are significantly improved. The rolled CoFeNiMnV HEAs are annealed at 500, 700 and 900 °C, for 60 min. The results show that annealing at 500 °C has little effect on the microstructure and dislocation density of the alloy, and the alloy still maintains high strength and hardness. With increasing of annealing temperature to 700 and 900 °C, the dislocation density of the CoFeNiMnV HEAs is significantly reduced. Meanwhile the σ phase is gradually dissolved, and the recrystallized grains and annealing twins are significantly coarsened. The analysis suggests that it decreases the strength of the CoFeNiMnV HEAs, but increases the elongation. CoFeNiMnV HEAs annealed at 700 °C for 60 min after CR exhibit an excellent high strength–toughness combination. [ABSTRACT FROM AUTHOR]

In this work, a plasma arc additive manufacturing technique with a double-wire feedback mechanism was used to manufacture Inconel 625 Ni–Cu functionally graded materials. The microstructure, mechanical properties and corrosion properties of the deposited alloy were evaluated. Microstructure observation and tensile testing of parts with different element contents indicated that functionally graded materials were obtained through the manufacturing process. The results have shown that due to the very high growth restriction factor Q of Cu, its addition can increase the constitutional supercooling zone, resulting in a decrease in columnar and dendrites and an increase in equiaxed crystals in the Inconel 625 Ni–Cu functionally graded material, as well as changing the Schmid factor (SF) distribution. The tensile strength and ductility of the Inconel 625 Ni–Cu functionally graded materials increased with increasing Cu content, while the corrosion resistance of the alloy decreased with increasing Cu content during electrochemical corrosion tests. [ABSTRACT FROM AUTHOR]

• EHEA was successfully prepared using D-WAAM technology for the first time. • Al 20.33 Co 21.60 Fe 30.45 Ni 27.62 EHEA consists of lamellar L1 2 and B2 phases. • EHEAs exhibit excellent strength and plasticity balance. Eutectic high entropy alloys (EHEAs) have received widespread attention due to their excellent mechanical properties. This letter successfully used double-wire arc additive manufacturing technology to prepare a new type of Al 20.33 Co 21.60 Fe 30.45 Ni 27.62 EHEA. Its phase composition, microstructure, and mechanical properties were characterized and studied. The alloy exhibited a biphasic lamellar eutectic microstructure composed of an ordered BCC (B2) phase and an ordered FCC (L1 2) phase. The ultimate tensile strength and elongation at room temperature are as high as 1022 MPa and 13.2 % respectively. Superior to most other EHEAs produced using casting and arc melting technologies. This approach has great potential in engineering applications. [ABSTRACT FROM AUTHOR]

• A new design strategy for Al-Cr-Co-Ni EMEAs. • A novel Al 17 Cr 17 Co 33 Ni 33 EMEA was prepared by PPA-AM. • The designed alloy exhibits eutectic lamellar structure of L1 2 and B2 phases. • The designed alloy possesses excellent mechanical performance. In this study, a new Al 17 Cr 17 Co 33 Ni 33 eutectic medium entropy alloy (EMEA) is designed and successfully fabricated by powder plasma arc additive manufacturing (PPA-AM). The microstructural investigation reveals that the alloy consists of ordered hard body-centered cubic B2 phase and ordered soft face-centered cubic L1 2 phase. The microhardness of the alloy is 335.54 Hv. And comparing to PPA-AMed AlCoCrFeNi 2.1 alloy, the designed alloy exhibits a high ultimate tensile strength of 1028 MPa and a high ductility of 19.09 % at the room temperature. And this represents a 17.89 %/32.57 % increase in ultimate tensile strength and ductility relative to a PPA-AMed AlCoCrFeNi 2.1 alloy, respectively. This is attributed to the phase interfacial strengthening caused by finer lamellar thickness. And the mechniacal properties reveal the Al 17 Cr 17 Co 33 Ni 33 alloy achieve the synergy of good tensile ductility and high fracture strength. [ABSTRACT FROM AUTHOR]

• Novel dual FCC phase Co-Cr-Fe-Ni-Cu-Mo HEA was designed and fabricated. • Combined cable wire is designed for additive manufacturing of HEA. • FCC HEA was greatly strengthened due to two phase structure. FCC phase High-entropy alloys (HEAs) has excellent plasticity and toughness but low tensile property. To strengthen the HEA without plasticity reducing, Cu 28.36 Ni 22.32 Fe 19.12 Co 15.17 Cr 12.26 Mo 2.77 HEA with dual FCC phase were successfully prepared by plasma arc additive manufacturing using a combined cable wire with multi-element composition. The results show that the prepared alloys were composed of Cu-poor FCC1 and Cu-rich FCC2, along with a small amount of Mo-rich precipitation phases. The ultimate tensile strength, yield strength is 531 MPa, 332 MPa, it is increased by 14.48 % and 32.75 % compared with arc melting technology with excellent elongation of 32.26 %. Compared with the vacuum induction melting technology, the strength is increased by 276.5 %. Dual phase obviously increased the mechanical properties. The Co and Cr element in the alloy is relatively low, which can reduce the production cost. [ABSTRACT FROM AUTHOR]