Unraveling the SCC behavior and enhanced creep strength mechanism of AFA alloy in supercritical CO2

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

Corrosion Science Pub Date : 2024-09-27 DOI:10.1016/j.corsci.2024.112488

Ming Shu , Shuo Cong , Qin Zhou , Xianglong Guo , Qiyin Zhou , Yongduo Sun , Songling Wu

引用次数: 0

Abstract

The oxide scale of 20Cr25Ni2.5Al AFA alloy formed under the coupling of stress and supercritical carbon dioxide (sCO₂, 650 ℃ / 15 MPa) consisted of Fe₃O₄, Cr₂O₃, preferential intergranular oxidation zones, but lacked a thin Al₂O₃ protective layer. The poor oxidation resistance resulted in significant CO₂ penetration into the matrix and subsequent formation of Cr₂O₃, thereby hindering the initiation of Cr - rich σ phase beneath the oxide scale. This competition between oxidation and precipitation effectively reduced crack initiation and delayed the connection between SCC and creep cracks, thus significantly prolonging the creep lifetime in sCO₂ compared to that in air.

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揭示 AFA 合金在超临界 CO2 中的 SCC 行为和蠕变强度增强机理

20Cr25Ni2.5Al AFA 合金在应力和超临界二氧化碳（sCO2，650 ℃ / 15 MPa）耦合作用下形成的氧化鳞片由 Fe3O4、Cr2O3、优先晶间氧化区组成，但缺乏薄的 Al2O3 保护层。较差的抗氧化性导致 CO2 大量渗入基体并随后形成 Cr2O3，从而阻碍了氧化鳞片下面富含 Cr 的 σ 相的形成。氧化和析出之间的这种竞争有效地减少了裂纹的产生，延缓了 SCC 和蠕变裂纹之间的联系，因此与空气中的蠕变寿命相比，sCO2 中的蠕变寿命大大延长。

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.