Control of mechanical properties of a high-entropy alloy Cantor CoCrFeMnNi

Abstract

A brief analysis of the work on changing the mechanical properties of the high-energy alloy (HEA) Cantor CoCrFeMnNi in various ways has been performed. The article describes the influence of alloying with aluminum, vanadium, manganese, titanium, silicon, carbon, copper on the hardening of wind turbines obtained by vacuum arc melting, laser melting, arc melting and drip casting, mechanical alloying with subsequent plasma sintering, gas sputtering followed by shock wave and static compaction. It is shown that additives of 2.5 % TiC and 5 % WC significantly improve the tensile strength, but reduce the elongation to failure. The effect of grain size in the range of 4.4 – 155 µm is to increase the tensile strength with a decrease in grain size. Lowering the temperature increases the strength and yield limits for grains of all sizes. Intensive plastic deformation forming nanoscale (~50 nm) grains significantly increases the tensile strength up to 1950 MPa and hardness up to 520 HV. Subsequent isochronous and isothermal annealing allows varying the strength and ductility of wind turbines. The formation of nanostructured-phase states during shock compounding, mechanical alloying and subsequent spark plasma formation significantly increase the tensile strength at room temperature, maintaining excellent plasticity (elongation of approximately 28 %). As one of the methods of modifying the mechanical properties of wind turbines, the authors propose electron-beam processing (EPO). The analysis of the deformation curves of the wind turbine, obtained by the technology of wire-arc additive production, after EPO with an electron beam energy density of 10 – 30 J/cm2, has been carried out; assumptions about the reasons for the decrease in strength and ductility characteristics have been found and substantiated. A comparative analysis of mechanical properties of the Cantor wind turbine obtained by various methods was carried out, and the reasons for discrepancy in the values of strength and plastic parameters were noted.