Influence of Si addition on the microstructure, mechanical and wear properties of as-cast Al0.43CoCrFeNi2.1 high-entropy alloys and performance enhancement by cold rolling and annealing

Cost-effective synthesis and thermomechanical processing of AlxCoCrFeNiCuy (x&y=0.5,1) high-entropy alloys

Development of cost-effective high-entropy alloys with superior mechanical properties

The article proves that important achievements of theoretical developments regarding the use of iron-based alloys are the scientific works of domestic researchers. Thus, in the dissertation research of Karpets M.V. for the first time, the phase composition, microstructure and physicо-mechanical properties of alloys of the Сr-Ni-Co-Fe-Cu-Al system in the concentration range (0-3 mol) of the content of chemical elements were systematically investigated. It was established that in the studied system, due to the high entropy of mixing, only simple solid substitution solutions based on fcc and bcc structures are formed, which are characterized by a high complex of physical and mechanical properties that are not inherent to any of the constituent components. It is substantiated that the main factor of phase formation in high-entropy alloys is the value of the average electron concentration of the alloy. The interval of values ​​of the average electron concentration, in which bcc or fcc structures exist, depends on the rate of crystallization of the melt and the presence of elements prone to liquation in the alloy. Stabilizing elements of solid solutions based on phases with bcc (Al, Cr) and fcc (Cu, Ni, Co) structures were established. A significant scientific achievement should be considered the first developed high-entropy CrMnFeCoNi2Cu alloy based on a solid solution with an fcc phase structure, capable of being deformed by rolling at room temperature by 98% without the appearance of cracks or tears. Its phase composition, microstructure, and physical and mechanical properties at all stages of deformation were studied. It is shown that, for the first time in Ukraine, during cold rolling in the high-entropy CrMnFeCoNi2Cu alloy, similar to pure metals and alloys with an fcc structure, a rolling texture with the main component appears. The article provides examples of other theoretical developments regarding the use of iron-based alloys.

Nanoscale high-entropy alloy for electrocatalysis

Improving mechanical properties of (Co1.5FeNi)88.5Ti6Al4R1.5 (R = Hf, W, Nb, Ta, Mo, V) multi-component high-entropy alloys via multi-stage strain hardening strengthening

Influence of Si addition on the microstructure, mechanical and lead-bismuth eutectic corrosion properties of an amorphous AlCrFeMoTiSix high-entropy alloy coating

Developing soft magnetic materials with high saturation magnetization, low coercivity, and excellent mechanical properties remains a challenge. This study investigates the FeCoNiMn 0.25 Al 0.25 high-entropy alloy fabricated via vacuum arc melting. To analyze the effect of strain path, unidirectional and bidirectional cold rolling were applied with thickness reductions of 20%, 50%, and 90%. X-ray diffraction confirmed a face-centered cubic phase in cold rolling samples, while annealing at 900 °C led to a dual-phase structure (face-centered cubic + minor body-centered cubic). Deformation texture analysis revealed α-fiber components in unidirectional-cold rolling samples and normal direction-rotated brass components in bidirectional-cold rolling samples, with annealing twins influencing the final recrystallization texture. The M s values increased to ∼114.6 and 111.8 emu/gram, while H c decreased to ∼242.3 and 231.7 A/m for 90% cold rolling followed by annealing in unidirectional and bidirectional samples, respectively. Mechanical testing showed high hardness, yield strength, and tensile strength in cold rolling conditions, with improved plasticity after annealing. The unidirectional-annealed samples exhibited the best balance of magnetic and mechanical properties, making this high-entropy alloy a strong candidate for electrical machinery, transformers, magnetic shielding, and power generation applications.

A novel high entropy alloy with outstanding strength by low temperature annealing after severe cold rolling

This work presented an upgraded high-entropy alloy by the addition of chromium to the conventional Ti-10V-2Fe-3Al alloy to fabricate equiatomic Ti20V20Al20Fe20Cr20 high-entropy alloy via spark plasma sintering powder processing at different temperature of 700 °C, 800 °C, 900 °C, 1000 °C, and 1100 °C respectively under a constant heating rate of 100 °C /min, the pressure of 40 MPa, and holding time of 5 min. The microstructure and phase transformation of the sintered alloyed were studied with a scanning electron microscope equipped with energy dispersive spectroscopy. The constituent phases present in the sintered high-entropy alloy were analyzed by X-ray diffraction and were found to show increased development of body-centered cubic solid solution alloys across the temperature gradients. The mechanical properties over a temperature range of 700 ≤ T °C ≤ 1100 generally show an increase in hardness from 3363 to 8480 MPa, tensile strength from 1097.17 to 2766.58 MPa, and yield strength from793.61 to 2001.13 MPa respectively. The SEM-EDS of Ti20V20Al20Fe20Cr20 equiatomic high-entropy alloys show the existence of a nano-net-like spinodal structure at the optimum temperature of 1100 °C, which are rich in body centered cubic structure. At this elevated temperature, the presence of strong body-centered cubic–forming elements such as Cr, Fe, and Al was established from the corresponding EDS. Ti20V20Al20Fe20Cr20 high-entropy equiatomic alloy has been successfully fabricated by spark plasma sintering. The effects of temperature on microstructural and mechanical properties of the sintered Ti20V20Al20Fe20Cr20 alloy demonstrated a general improvement of the alloys at the elevated region.

Comparative study of microstructure and mechanical properties of cold rolled and annealed CoCrFeNi-MEA and CoCrFeNiMn-HEA fabricated by laser energy deposition

Effects of Er2O3 contribution on microstructure and mechanical properties of high entropy and dual phase alloys

Synergy effect of multi-strengthening mechanisms in FeMnCoCrN HEA at cryogenic temperature

A novel complex-structure Co-free Cr-Fe-Ni-Al-Si-Ti-Cu high entropy alloy with outstanding mechanical properties in as-cast and cold-rolled states

Effects of Si addition on microstructure, mechanical and thermal fatigue properties of Zn-38Al-2.5Cu alloys

High entropy alloys (HEAs), composed of multiple components with equal or near atomic proportions, have extraordinary mechanical properties and are expected to bear the impact of high-speed forces in armor protection structure materials. In order to understand the deformation behaviour of HEAs under tensile and compressive loading, molecular dynamics simulations were performed to reveal the deformation mechanism and mechanical properties of three crystal structures: Al0.1CoCrFeNi HEAs without grain boundaries (perfect HEAs), Al0.1CoCrFeNi HEAs with grain boundaries of Σ3(111)[11̄0] (GBs HEAs) and grain boundaries of Σ3(111)[11̄0] with chemical cluster HEAs (cluster-GBs HEAs). The mechanical properties of the three models at the same strain rate were discussed. Then, the mechanical properties at different strain rates were analyzed. The movement and direction of internal dislocations during the deformation process were investigated. The simulation results show that the GBs HEAs and the cluster-GBs both play an important role in the deformation and failure of the HEAs. Under tensile loading, three behaviour stages of deformation were observed. Cluster-GBs HEAs have a larger yield strength and Young's modulus than that of GBs and perfect HEAs. The higher the strain rate is, the greater the stress reduction rate. Under compressive loading, there are only two behaviour stages of deformation. Cluster-GBs HEAs also have the largest yield strength. Under tensile and compressive deformation, Shockley partial dislocations of 1/6 <112> are dominant and their moving direction and effect on mechanical properties are discussed.