OBRABOTKAMETALLOV MATERIAL SCIENCE Vol. 26 No. 4 2024 Ta b l e 2 Comparison of predicted and experimental yield strengths of various alloys High entropy alloy Temperature, °C Predicted yield strength, MPa Experimental yield strength, MPa Error (%) MoNbTaTiW [60] 1,200 572 585 2.5 AlCrNbTiVZr [61] 600 1,409 1,093 13 AlCrNbTiVZr [62] 600 837 845 1 and operating conditions. This can help improve the accuracy of alloy property predictions and optimize the processes for developing new materials with specifi ed characteristics. Plasticity and Deformability Research The study of the plasticity and deformability of HEAs is a signifi cant fi eld because these properties are essential for its application in various industries. This topic is covered by researchers from diff erent perspectives: the plastic deformation of HEAs under mechanical processing is studied [63], as well as the simultaneous enhancement of the strength and plasticity of HEAs through purifi cation mechanisms [64]. The eff ect of electron irradiation on the microstructure and plasticity after annealing at intermediate temperatures is also examined. The essence of irradiation-induced plasticity lies in the refi nement and redistribution of nanoprecipitates. Optimization of the size and distribution improved the interaction between nanoprecipitates and dislocations, eff ectively preventing brittle fractures caused by stress concentration [65]. Increased thermal stability and plasticity of HEAs is achieved by introducing hard and brittle borides. Borides signifi cantly increase the material plasticity without compromising its strength. In addition, a chemical order-disorder transition occurs near borides, which improves the mobility of dislocations and promotes plastic deformability of the material. The presence of stable borides also prevents grain growth in the material at high temperatures, as the borides pin the grains and stabilize its size [66]. Thus, this section emphasizes the importance of a comprehensive approach to developing and improving HEAs, including the synthesis of new alloys, refi ning processing methods, and using modern modeling and forecasting technologies. This contributes to the creation of materials with unique combinations of strength and plasticity properties, necessary for use in extreme operating conditions. Electrical and Magnetic Properties Research into HEAs in the fi elds of electrical and magnetic properties provides new opportunities for creating materials with unique electromagnetic characteristics, enabling the development of energy-effi cient technologies, electrical conductors, sensors, or electronic components. Changes in the electrical conductivity of HEAs depend on several factors, such as alloy composition, temperature, pressure, and impurities. Annealing is an important method for infl uencing the electrical conductivity properties of HEAs. Thermal treatment can lead to changes in the alloy’s microstructure, including grain recrystallization, dislocation reduction, and phase composition alterations, aff ecting the material electrical conductivity. For example, annealing can help restore electrical conductivity after mechanical deformation or improve the structural uniformity of the alloy [67, 68]. Pressure can aff ect the change in electrical conductivity. In the normal state, the TiZrHfNb alloy demonstrates high electrical resistance, which is almost independent of temperature but signifi cantly dependent on pressure; it decreases linearly by 12.5 % with an increase in pressure to 5.5 GP [69]. Regarding electrical conductivity, there is a study devoted to surface treatment using ultrasonic electropulse rolling [70]. The study used fi ve elements: chromium (Cr), manganese (Mn), iron (Fe), cobalt (Co), and nickel (Ni), with a high purity level (99.9 %) and an equimolar ratio. These elements were melted in a vacuum melting furnace using electromagnetic induction, ensuring a high degree of alloy composition uniformity.
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