This study investigated the hydrogen embrittlement behavior of 316 austenitic stainless steel subjected to hydrogen charging at different temperatures, using slow strain-rate testing and acoustic emission (AE) techniques. Compared to the noncharged specimen, the specimen H-charged at 25 °C exhibited similar elongation and a ductile fracture mode, while hydrogen charging at 60 °C led to a pronounced reduction in elongation accompanied by quasi-cleavage fracture. This degradation may be associated with enhanced hydrogen transport and redistribution at the elevated charging temperature, which could increase the effective hydrogen activity at microstructural sites, known to be critical to crack initiation and propagation. Feritscope measurements indicated a relative increase in strain-induced martensite formation in the hydrogen-charged specimens. Specifically, the H-charged at 25 °C specimen showed a localized increase in martensite near the fracture surface, and the H-charged at 60 °C specimen exhibited a high martensite fraction over the measured region of the gauge section. AE analysis showed that the cumulative number of AE events decreased after hydrogen charging, while the cumulative absolute energy increased, particularly for the H-charged at 60 °C specimen. These results suggest a relative change in fracture behavior under hydrogen-charged conditions, from ductile fracture involving numerous low-energy AE events to more abrupt fracture behavior characterized by fewer but more energetic AE events. This study suggests that AE analysis can serve as a complementary tool for characterizing deformation and the fracture behavior associated with hydrogen embrittlement in austenitic stainless steels.

Abstract
1. 서 론
2. 실험 방법
3. 결과 및 고찰
    3.1. 미세조직
    3.2. 수소 충전 온도에 따른 인장 결과 및 파괴 거동
    3.3. 마르텐사이트 변태 및 AE 거동 분석
4. 결 론
Acknowledgement
References
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• 민기득(주식회사 피레타) | Ki-Deuk Min (Pileta Co., Ltd., Daejeon 34000, Republic of Korea)
• 최수환(서울과학기술대학교 신소재공학과) | Su-Hwan Choe (Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea)
• 신승혁(서울과학기술대학교 신소재공학과) | Seung-Hyeok Shin (Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea)
• 황병철(서울과학기술대학교 신소재공학과) | Byoungchul Hwang (Department of Materials Science and Engineering, Seoul National University of Science and Technology, Seoul 01811, Republic of Korea) Corresponding author