Amorphization under fracture surface in hydrogen-charged and low- temperature tensile-tested austenitic stainless steel. (2nd January 2021)

• Record Type: Journal Article
• Authors: Harada, A.; Kusunoki, K.; Moritani, K.; Matsumoto, K.; Hatano, M.; Horibe, Y.
• Is Part Of: Philosophical magazine letters. Volume 101:Number 1(2021)
• Page Start: 40
• Page End: 50
• Publication Date: 2021-01-02
• Subjects: Amorphous -- transmission electron microscopy -- hydrogen charging -- fracture surface -- stable austenitic stainless steel; Condensed matter -- Periodicals; Physics -- Periodicals; Solid state physics -- Periodicals; Physique -- Périodiques; 530.41
• DOI: 10.1080/09500839.2020.1841915
• Languages: English
• ISSNs: 0950-0839

Abstract

ABSTRACT: The microstructure just below the fracture surface in hydrogen-charged stable austenitic SUS 316L stainless steel, which was subjected to a low strain rate tensile test at −70°C, was studied by a combination of the focused-ion-beam method and transmission electron microscopy. An amorphous region with a chemical composition almost identical to that of the polycrystalline region was found under the lath-like structure on the fracture surface, although no deterioration of tensile properties by hydrogen appeared. In the amorphous region, band-like regions with wavy contrasts were observed, which were often accompanied by cracks at the boundaries. The presence of the amorphous region with band-like regions implies that amorphization occurred due to high-density vacancies accompanied by agglomerations of excess vacancies in the hydrogen-charged SUS 316L stainless steel that was tensile-tested at low temperatures.