Phases, Microstructures and Mechanical Properties of CoCrNiCuZn High-Entropy Alloy Prepared by Mechanical Alloying and Spark Plasma Sintering

Abstract

In the study, an equiatomic CoCrNiCuZn high-entropy alloy (HEA) was prepared by mechanical alloying (MA) and the phases, microstructures, and thermal properties of the alloy powder were explored. The results suggest that a solid solution with body-centered cubic (BCC) phase and a crystalline size of 10 nm formed after 60 h of milling. Subsequently, the alloy powder was consolidated by spark plasma sintering (SPS) at different temperatures (600 °C, 700 °C, 800 °C, and 900 °C). Two kinds of face-centered cubic (FCC) phases co-existed in the as-sintered samples. Besides, Vickers hardness and compressive strength of the consolidated alloy sintered at 900 °C were respectively 615 HV and 2121 MPa, indicating excellent mechanical properties.

An Overview of High-Entropy Alloys Prepared by Mechanical Alloying Followed by the Characterization of Their Microstructure and Various Properties

“…The CoCrNiCuZn HEAs were prepared by Sun et al using a planetary ball mill for 60 h with a BPR and mill speed of 20:1 and 300 rpm, respectively [33]. The fabricated HEAs were consolidated by SPS and their microstructures, phases, and mechanical properties were studied.…”

“…They reported that the fabricated HEA exhibited a crystallite size of 10 nm and a BCC structure after 60 h of milling. After the consolidation of HEA powders by SPS, the authors observed two different FCC phases, as shown in Figure 10, and named them as FCC1 and FCC 2, respectively [33]. They studied the Vickers microhardness and compressive strength of the SPS-consolidated HEA (900 • C) samples, and the values were found to be 615 HV and 2121 MPa, respectively.…”

“…They studied the Vickers microhardness and compressive strength of the SPS-consolidated HEA (900 • C) samples, and the values were found to be 615 HV and 2121 MPa, respectively. The CoCrNiCuZn HEAs were prepared by Sun et al using a planetary ball mill for 60 h with a BPR and mill speed of 20:1 and 300 rpm, respectively [33]. The fabricated HEAs were consolidated by SPS and their microstructures, phases, and mechanical properties were studied.…”

New Advances in High-Entropy Alloys

“…Multi-phase microstructures formed in the alloys, which can be attributed to the large lattice strain and negative enthalpy of mixing, caused by the addition of Zr. Sun et al [ 23 ] also employed the mechanical alloying technique and prepared the CoCrNiCuZn alloy. Pd addition promoted the local- and long-range lattice distortions in CoCrFeNi alloy and also had effect on the phase stability and phase transformation.…”