Structure peculiarities of rapidly quenched high-entropy alloy (Fe0.25Co0.25Ni0.25Cr0.125V0.125)95B5

This paper investigates the effect of melt quenching on the multicomponent alloy (Fe0.25Co0.25Ni0.25Cr0.125V0.125)95B5, with a particular focus on the microstructure and the formation of a single-phase state of a multicomponent solid solution. Samples were produced at various cooling rates, which were set by choosing an appropriate rotation speed of the copper wheel. A range of analytical methods, including SEM, XRD, TEM and EELS, was employed to investigate the influence of the cooling rate on the alloy structure formation during quenching. In circumstances where the rate of cooling is minimal, the alloy structure typically exhibits a hypoeutectic structure of the kind consisting of FCC solid solution dendrites and borides. It has been demonstrated that an increase in the cooling rate results in the formation of a single-phase structure of a boron-supersaturated FCC solid solution. It has been demonstrated that the solubility of boron in multicomponent solution is considerably influenced by the density of grain boundaries, which act as sites of preferential boron segregation during the process of crystallization. The second most significant factor in the formation of a single-phase structure during the quenching of a liquid is the suppression of boron diffusion during crystallization due to an increase in the cooling rate. It has been demonstrated that, in order to form a single-phase state in the structure of the (Fe0.25Co0.25Ni0.25Cr0.125V0.125)95B5 alloy, it is necessary to increase the cooling rate during melt quenching to speeds at which the linear growth rate of crystals is almost completely suppressed.

1. Russian Science Foundation - No. 22-79-10055-P