Influence of Factors on the Structure and Properties of High-entropy FeCrMnCoNi Alloy

The homogeneity of structure and physical properties (texture, microstructure, microhardness, magnetic susceptibility) for samples of high-entropy FeCrMnCoNi alloy cut from ingot after partial homogenization was investigated. On the example of one sample, it was showed that the microhardness, HV, along the sample is not a constant, but is characterized by a certain distribution. X-ray studies of the fragments obtained by cutting this sample showed that each fragment was characterized by its texture. Degree and character of texture was estimated using the Wilson parameter. Scanning electron microscopic studies also show the heterogeneous nature of the structure distribution for each fragment, that is, the heterogeneous nature of the structure along the sample. Investigation of the magnetic properties by the Faraday method also allowed to establish the inhomogeneity of magnetic parameters (magnetic susceptibility, localized magnetic moment) along the samples, which is retained even in the case of additional deformation in the preparation of samples for research. Comparison of the presented parameter distributions and some parameters that are not included in the results (the size of coherent scattering regions, microstrains, density of the stacking faults) revealed no correlation between the investigated values. However, the study of the average composition of each fragment did not reveal a significant deviation of the composition from the nominal. On the basis of this, it is assumed that such inhomogeneity of the parameters under the condition of constant composition is a consequence of temperature gradients during the formation of the ingot and/or temperature gradients and the inhomogeneous nature of the deformation during the manufacture of the samples. Change in the balance between enthalpy and entropy contributions at low temperatures is considered one of the reasons for this heterogeneity. It is suggested that this leads to changes in the nature of the short-range order, which generally does not destroy the structure of the high-entropy alloy, but strongly affects the physical parameters.