Effect of boron segregation on hydrogen-induced grain boundary embrittlement in CoCrFeNi medium-entropy alloys

IF 7.4 1区材料科学 Q1 MATERIALS SCIENCE, MULTIDISCIPLINARY

Corrosion Science Pub Date : 2025-09-15 DOI:10.1016/j.corsci.2025.113320

Hyun Jeong , Ji Yoon Jeong , Soo Yeol Lee , KenHee Ryou , Pyuck-Pa Choi , Yakai Zhao , Siyuan Wei , Pei Wang , Dong-Hyun Lee

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Abstract

Hydrogen embrittlement (HE) degrades the mechanical performance of metals in hydrogen environments, posing challenges to the safety and reliability of hydrogen energy systems. Although face-centered cubic (FCC) high-/medium-entropy alloys (H/MEAs) show promise due to their intrinsic HE resistance, intergranular failure still occurs under extreme conditions. This study investigated the effect of boron doping on hydrogen-induced grain boundary (GB) embrittlement in CoCrFeNi MEAs under as-cast conditions. Approximately 80 wt. ppm boron was added without altering the microstructure of the alloy. In-situ hydrogen charging tensile tests revealed that boron doping significantly reduced ductility loss, with the HE index decreasing from ∼82 % to ∼32 %, and shifted the fracture mode from intergranular to transgranular. Atom probe tomography confirmed selective boron segregation at the GBs. Thermal desorption spectroscopy and Ag decoration experiments demonstrated that boron suppressed hydrogen trapping at GBs by occupying interstitial sites. Spherical nanoindentation showed decreased critical shear stress for GB slip transmission in the boron-doped alloy, suggesting enhanced GB plasticity. These combined effects of strengthened GB cohesion, reduced hydrogen accumulation, and improved slip transmission synergistically contributed to the enhanced HE resistance of the boron-doped CoCrFeNi MEA.

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硼偏析对CoCrFeNi中熵合金氢致晶界脆化的影响

氢脆（HE）降低了金属在氢环境中的机械性能，对氢能源系统的安全性和可靠性提出了挑战。虽然面心立方（FCC）高/中熵合金（H/MEAs）由于其固有的HE阻力而表现出良好的前景，但在极端条件下仍然会发生晶间破坏。本文研究了铸态条件下硼掺杂对CoCrFeNi MEAs中氢致晶界（GB）脆的影响。大约80 wt。在不改变合金组织的情况下加入PPM硼。原位充氢拉伸试验表明，硼的掺入显著降低了塑性损失，HE指数从~ 82 %降至~ 32 %，断裂模式由晶间断裂转变为穿晶断裂。原子探针层析成像证实了在GBs处的选择性硼偏析。热解吸光谱和银装饰实验表明，硼通过占据间隙位抑制了硼原子上的氢捕获。球形纳米压痕降低了硼掺杂合金GB滑移传递的临界剪切应力，表明硼掺杂合金的GB塑性增强。这些增强GB内聚、减少氢积累和改善滑移传输的综合作用共同促进了掺硼CoCrFeNi MEA抗HE性能的增强。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

Corrosion Science 工程技术-材料科学：综合

CiteScore

13.60

自引率

18.10%

发文量

763

审稿时长

46 days

期刊介绍： Corrosion occurrence and its practical control encompass a vast array of scientific knowledge. Corrosion Science endeavors to serve as the conduit for the exchange of ideas, developments, and research across all facets of this field, encompassing both metallic and non-metallic corrosion. The scope of this international journal is broad and inclusive. Published papers span from highly theoretical inquiries to essentially practical applications, covering diverse areas such as high-temperature oxidation, passivity, anodic oxidation, biochemical corrosion, stress corrosion cracking, and corrosion control mechanisms and methodologies. This journal publishes original papers and critical reviews across the spectrum of pure and applied corrosion, material degradation, and surface science and engineering. It serves as a crucial link connecting metallurgists, materials scientists, and researchers investigating corrosion and degradation phenomena. Join us in advancing knowledge and understanding in the vital field of corrosion science.