Phase transformations and relaxation phenomena caused by hydrogen in stable austenitic stainless steel

Journal Article · Wed Feb 01 04:00:00 EST 1995 · Acta Metallurgica et Materialia

DOI:https://doi.org/10.1016/0956-7151(94)00272-J· OSTI ID:27888

Gavriljuk, V G; Tarasenko, A V; Tereshchenko, A S ^[1]; Haenninen, H; Ullakko, K ^[2]

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1. Inst. for Metal Physics, Kiev (Ukraine)
2. Helsinki Univ. of Technology, Espoo (Finland)

Stable austenitic stainless Cr18Ni16Mo10 steels alloyed with different nitrogen content were studied by means of X-ray diffraction, internal friction and Moessbauer spectroscopy. Cathodic charging induces the {epsilon}{sub H} phase. No evidence is obtained for occurrence of the hydrogen-induced {gamma}{sub H} phase which could be interpreted in terms of spinodal decomposition of the hydrogen solid solution. Nitrogen retards the formation of the {epsilon}{sub H} phase and increases the fraction of the hydrogen-rich {gamma} solid solution. The beneficial effect of nitrogen on hydrogen-caused losses of the mechanical properties can be attributed to the suppression of the {epsilon}{sub H} phase formation. The internal friction spectrum of hydrogenated stable austenitic stainless steels consists of five peaks three of which are of the relaxation nature and other two correspond to hysteretic processes. The hydrogen-induced relaxation in austenite can be described by the Snoek-like mechanism concerned with the reorientation of complexes of hydrogen atoms with substitutional solutes. The ideas of H-H reorientation and hydrogen-induced Snoek-Koester relaxation in austenite are not confirmed. Short range atomic order changed by means of cold work or electron irradiation affects the relaxation spectrum. Addition of nitrogen prevents the relaxation concerned with a short range migration of the hydrogen atoms, which can be attributed to the nitrogen suppression of the {epsilon}{sub H} phase. Hysteretic damping is caused by outgassing of hydrogen from the samples.

• OSTI ID: 27888
• Journal Information: Acta Metallurgica et Materialia, Journal Name: Acta Metallurgica et Materialia Journal Issue: 2 Vol. 43; ISSN 0956-7151; ISSN AMATEB
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
AUSTENITIC STEELS
HYDROGEN
INTERNAL FRICTION
MECHANICAL PROPERTIES
METALLURGICAL EFFECTS
MICROSTRUCTURE
NITROGEN
PHASE TRANSFORMATIONS
RELAXATION