Data related to the growth of σ-phase precipitates in CrMnFeCoNi high-entropy alloys: Temporal evolutions of precipitate dimensions and concentration profiles at interfaces

A data compilation related to the growth kinetics of a topologically closed-packed (TCP) phase is reported. A high-entropy alloy (HEA) with a composition of Cr(26)Mn(20)Fe(20)Co(20)Ni(14) in at.%, a mean grain size of 50 µm and initially single-phase face-centered cubic (FCC) was annealed at temperatures ranging from 600 °C to 1000 °C for times between 0.05 h and 1000 h. These heat treatments resulted in the formation of tetragonal σ precipitates that formed heterogeneously at different elements of the microstructure. The raw data of the present article include backscattered electron (BSE) micrographs where σ precipitates can be observed within grains, at grain boundaries, and triple points of the FCC matrix. From these images, the dimensions of the five largest precipitates observed within grains and those of the five largest allotriomorphs are provided for different times and temperatures in tables. As the σ precipitates are more enriched in Cr and depleted in Ni than the surrounding matrix, Cr-depleted (Ni-enriched) zones form in the FCC matrix next to the precipitates and widen at rates determined by diffusion. To document the evolution of the corresponding concentration profiles with time, electron dispersive X-ray spectroscopy (EDX) was used and the data are reported in Excel files. From these concentration profiles, the widths of the diffusion affected zones for Ni and Cr were systematically determined at different temperatures and times, apparent diffusion coefficients were deduced and all these data are provided in tables. The research data reported here have a fundamental value and document the growth kinetics of σ precipitates within grains and at grain boundaries. These data may help to establish a model able to predict how the precipitation kinetics of σ particles in FCC HEAs is affected by the alloy grain size and how the microstructure (volume fraction, size and distribution of σ precipitates) evolves with time and temperature. This approach may also be extended to austenitic steels and superalloys.