Scholarlink

<p>The high-temperature phase stability and microstructural evolution of a novel Co-free AlCrFeNi<sub>3</sub> eutectic high-entropy alloy (EHEA) were systematically investigated for potential elevated-temperature applications. The alloy was subjected to isothermal annealing at 900°C and 1100°C for durations ranging from 1&#xa0;h to 400&#xa0;h, and the results demonstrated excellent phase stability with no deleterious tertiary phases forming after prolonged exposure, but its morphology underwent a temperature-dependent degradation. At 900°C, the microstructure evolved into a mixture of coarsened lamellae and spheroidized B2 particles, whereas, at 1100°C, it transformed completely into coarse B2 particles uniformly dispersed in an FCC matrix. This microstructural coarsening, driven by enhanced lamellar boundaries elemental partitioning and accelerated colony boundaries diffusion at higher temperatures, led to a non-monotonic evolution of Vickers hardness, reflecting a competition between softening from Ostwald ripening and strengthening from potential precipitation. Quantitative EBSD analysis revealed that near-equilibrium phase fractions (~&#xa0;71% FCC, ~ 27% B2) were established after 400 h at both temperatures. Furthermore, kernel average misorientation maps confirmed substantial relief of internal strains, with average values as low as ~ 0.65°, indicating that microstructural evolution proceeded via in-situ coarsening without recrystallization. This work elucidates the kinetic pathways governing the high-temperature stability of Co-free EHEAs and provides critical insights for tailoring their microstructure and properties for service in extreme environments.</p>

错误：搜索内容不能为空，请输入英文关键词
错误：关键词超出字数限制，请精简
高级检索

Phase Stability and Coarsening Mechanism of AlCrFeNi3 Eutectic High-Entropy Alloy at 900°C and 1100°C

  • 期刊论文

  • 发表日期：

    2026年6月25日

查看全文
  • Yong Dong,
  • Haoran Zhai,
  • Shougang Duan,
  • Huiting Zheng

摘要

The high-temperature phase stability and microstructural evolution of a novel Co-free AlCrFeNi3 eutectic high-entropy alloy (EHEA) were systematically investigated for potential elevated-temperature applications. The alloy was subjected to isothermal annealing at 900°C and 1100°C for durations ranging from 1 h to 400 h, and the results demonstrated excellent phase stability with no deleterious tertiary phases forming after prolonged exposure, but its morphology underwent a temperature-dependent degradation. At 900°C, the microstructure evolved into a mixture of coarsened lamellae and spheroidized B2 particles, whereas, at 1100°C, it transformed completely into coarse B2 particles uniformly dispersed in an FCC matrix. This microstructural coarsening, driven by enhanced lamellar boundaries elemental partitioning and accelerated colony boundaries diffusion at higher temperatures, led to a non-monotonic evolution of Vickers hardness, reflecting a competition between softening from Ostwald ripening and strengthening from potential precipitation. Quantitative EBSD analysis revealed that near-equilibrium phase fractions (~ 71% FCC, ~ 27% B2) were established after 400 h at both temperatures. Furthermore, kernel average misorientation maps confirmed substantial relief of internal strains, with average values as low as ~ 0.65°, indicating that microstructural evolution proceeded via in-situ coarsening without recrystallization. This work elucidates the kinetic pathways governing the high-temperature stability of Co-free EHEAs and provides critical insights for tailoring their microstructure and properties for service in extreme environments.