Spinodal Decomposition of B2-phase and Formation of Cr-Rich Nano-precipitates in AlCoCrFeNi2.1 Eutectic High-Entropy Alloy

Javad Charkhchian, Abbas Zarei-Hanzaki, Ali Moshiri, Hamid Reza Abedi, Tim M. Schwarz, Robert Lawitzki, Guido Schmitz, Kanwal Chadha, Clodualdo Aranas, Jiajia Shen, João Pedro Oliveira

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

Herein, the occurrence of a B2-phase separation and formation of Cr-rich nano-precipitates during the solidification process of AlCoCrFeNi2.1 eutectic high-entropy alloy is addressed. Toward this end, various advanced characterizations, including high-resolution transmission electron microscopy and atom probe tomography combined with thermodynamic calculations, are employed. The as-solidified microstructure is composed of face-centered cubic (FCC) dendrites and interdendritic regions consisting of a eutectic mixture of FCC and body-centered cubic (BCC) phases. The presence of uniformly distributed Cr-rich nano-precipitates is traced through the BCC B2 phase in the interdendritic area. Regarding the occurrence of upward diffusion and Gibbs free energy variation, the formation of Cr-rich nano-precipitates is attributed to the spinodal decomposition where the critical temperature of 800 °C is passed behind during the solidification process. The formation of dense dislocation array in the interdendritic region due to thermal stress induced during solidification is introduced as a pathway for diffusion of alloying elements in the course of cooling stage.

Original languageEnglish
Article number2300164
Number of pages10
JournalAdvanced Engineering Materials
Volume25
Issue number16
DOIs
Publication statusPublished - Aug 2023

Keywords

  • Cr-rich nano-precipitate
  • eutectic high-entropy alloy
  • phase separation
  • spinodal decomposition

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