Micro-mechanical characterisation of hydrogen embrittlement in nano-twinned metastable austenitic stainless steel. (16th October 2020)

• Record Type: Journal Article
• Authors: Ueki, Shohei; Oura, Ryuji; Mine, Yoji; Takashima, Kazuki
• Is Part Of: International journal of hydrogen energy. Volume 45:Number 51(2020)
• Page Start: 27950
• Page End: 27957
• Publication Date: 2020-10-16
• Subjects: Hydrogen embrittlement -- Austenitic stainless steel -- Nano-twinned structure -- Micro-tensile test; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2020.07.120
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: Micro-tensile tests were performed on single variants of nano-twinned 304 stainless steel with hard and soft orientations to determine the effect of nano-twins on hydrogen embrittlement in the metastable austenitic steel. Nano-twins were introduced into the 304 steel by deformation above the martensite-start temperature. The introduction of nano-twins increased the yield stress to 647 MPa for the hard-oriented crystals and 540 MPa for the soft-oriented crystals. For the soft-oriented crystals, the hydrogen charge induced quasi-cleavage although it did not change the uniform strain. For the hard-oriented crystals, the introduction of nano-twins retarded hydrogen-induced twin boundary separation. The relationship between the reduction of area and ultimate tensile strength revealed that the degree of strengthening and mitigation of hydrogen-induced ductility loss depended on the orientation of the nano-twins. These suggest that controlling the orientation and distribution of nano-twins allows for simultaneous strengthening and mitigation of hydrogen-induced ductility loss in metastable austenitic steel. Highlights: Nano-twins were introduced in type 304 steel via 40% warm deformation. Micro-tensile tests were performed on single crystals of nano-twinned 304 steel. Yield stress was significantly increased by introduction of nano-twins. Hydrogen-induced premature failure was retarded by introduction of nano-twins.