Effect of aluminum on fine structure and distribution of chemical elements in high-entropy alloys Al x FeNiCoCuCr

Abstract

Electron microscopic and X ray diffraction methods have been used to study the fine structure of cast high entropy alloys (HEAs) Al x FeNiCoCuCr (x = 1, 1.5, 1.8). Disperse precipitates with dimensions of 130-400 and 10-20 nm have been revealed, the character of distribution of which, as well as the amounts, dimensions, and shapes, change with increasing aluminum content. In the equiatomic HEA, copper con taining particles with an fcc structure have been found; in the alloy with x = 1.8, particles of bcc Al 4 Cu 9 dom inate. It has been shown that the most uniform distribution over the matrix is characteristic of Co, unlike other elements, among which Cu and Cr are distributed in the alloy extremely nonuniformly and predomi nantly enter into the precipitated particles and into clusters in the interparticle spaces, respectively. Ni CrFe Co Fig. 4. Maps of the distribution of chemical elements over the volume of the region of the structure of the alloy А 3 shown in Fig. 3.

Tracer Diffusion of Cobalt in High-Entropy Alloys Al$_{x}$FeNiCoCuCr

“…2, b). The inhomogeneous atomic distribution in the Al x FeCoNiCuCr HEA was detected in [16][17][18]. Particularly Cu tends to segregate in ID-DR boundaries [16,18], which results from a high positive enthalpy of mixing of Cu in the mixture with the other elements [16,19].…”

“…Particularly Cu tends to segregate in ID-DR boundaries [16,18], which results from a high positive enthalpy of mixing of Cu in the mixture with the other elements [16,19]. Taking into account the spatial inhomogeneities in the as-cast Al x FeCoNiCuCr HEA [16][17][18], their multiphase composition and dendritic microstructure [1-3] (see Fig. 1 and Fig.…”

Mössbauer and Ultrasonic Study of the As-Cast High-Entropy Al$_x$CuCrCoNiFe Alloys

“…structure. It is possible that zero field peak is attributed to Fe atoms in copper precipitates, which according to TEM data are distributed inhomogeneously mainly on DR-ID boundaries [27,28]. However, this contribution could be low through low mutual dissolution of iron and copper.…”

Structure of Ion-Plasma Sprayed Coatings Made of a High-Entropy AlFeNiCoCuCr Alloy

“…Таким образом, электронно-микроскопические исследования выявили новые морфологические особенности и дополнительные фазовые составляющие в литом эквиатомном ВЭС AlCuCoFeNiCr по сравнению с результатами работ [9,17,18], что связано, по-видимому, с другой скоростью охлаждения слитка, которая опре-деляет особенности кристаллизации и распада твёрдых растворов. ИП-покрытия.…”

“…Полученные данные не согласуются с рентге-новскими по числу фаз (рис. 3) из-за разного разрешения методов и не противоречат мёссбауэровским [17], свидетельствующим об осо-бенностях распределения химических элементов в покрытиях из ВЭС в условиях увеличения вероятности ситуативных связей при разных температурах и скоростях охлаждения.…”