Zhuqun Zhang , Jingyu Pang , Yitong Yang , Zhenqiang Xing , Long Zhang , Yuan Sun , Aimin Wang , Hongwei Zhang
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引用次数: 0
Abstract
The microstructural and mechanical stability of high-temperature structural materials under prolonged high-temperature exposure critically governs their in-service performance and operational reliability. In this study, we developed a novel L12-nanoparticle-strengthened high-entropy alloy (HEA) and quantitatively investigated the evolution of its grain size, L12 precipitates, and grain boundary (GB) precipitation during isothermal aging at 750 °C. Results reveal that the developed HEA maintains exceptional microstructural stability, with limited grain size fluctuation, slow coarsening kinetics (coarsening rate constant of 1.64 × 10−29 m3/s), and minimal topologically close-packed (TCP) precipitates at GBs (<0.31 %) after 2000 h aging. Notably, the coarsening kinetics of L12 precipitates in this HEA are significantly lower than those of other L12-strengthened HEAs and typical Ni-based superalloys. The superior microstructural stability of HEA ensures remarkable mechanical stability over a wide temperature range. Despite inducing trace TCP phase precipitation that reduces high-temperature elongation below 3 % after the aging time of 500 h, extended aging time restores ductility while maintaining yield strength above 700 MPa, demonstrating exceptional mechanical stability under long-time aging. This study validates HEAs' exceptional microstructure and mechanical stability at high temperatures, highlighting its potential for advanced high-temperature structural applications.
期刊介绍:
Materials Science and Engineering A provides an international medium for the publication of theoretical and experimental studies related to the load-bearing capacity of materials as influenced by their basic properties, processing history, microstructure and operating environment. Appropriate submissions to Materials Science and Engineering A should include scientific and/or engineering factors which affect the microstructure - strength relationships of materials and report the changes to mechanical behavior.