Evaluation of the role of Mo2C in hydrogen induced ductility loss in Q&T FeCMo alloys. (24th August 2016)

• Record Type: Journal Article
• Authors: Depover, T.; Verbeken, K.
• Is Part Of: International journal of hydrogen energy. Volume 41:Number 32(2016)
• Page Start: 14310
• Page End: 14329
• Publication Date: 2016-08-24
• Subjects: Hydrogen embrittlement -- Hydrogen trapping -- Diffusible hydrogen -- Thermal desorption spectroscopy -- In-situ mechanical testing; Hydrogen as fuel -- Periodicals; Hydrogène (Combustible) -- Périodiques; Hydrogen as fuel; Periodicals; 665.81
• DOI: 10.1016/j.ijhydene.2016.05.176
• Languages: English
• ISSNs: 0360-3199

Abstract

Abstract: The hydrogen induced ductility loss of three FeCMo alloys is evaluated in this work and correlated with the hydrogen interaction of the Mo2 C precipitates. Two thermal treatments are applied to compare two main conditions; i.e. an as-quenched and a quenched and tempered state in which Mo2 C particles have precipitated. The susceptibility to hydrogen embrittlement is determined by performing tensile tests on both uncharged and hydrogen charged tensile specimen. Tempering appears to reduce the resistance against hydrogen embrittlement. Hot/melt extraction and thermal desorption spectroscopy are subsequently performed to determine the role of the Mo2 C precipitates. Tempered induced Mo2 C particles trap a considerable amount of hydrogen and a correlation between the hydrogen embrittlement susceptibility and the hydrogen mobility is confirmed. A slightly modified thermal treatment and charging procedure allows evaluating these interpretations. Moreover, the crucial role of hydrogen diffusion is tested by lowering the tensile test speed on hydrogen pre-charged and non-pre-charged specimens. Highlights: The effect of hydrogen charging on FeCMo alloys is evaluated by tensile tests. H absorption, trapping and diffusion are determined by H characterization methods. A correlation between the degree of HE and the amount of mobile H was established. The combined role of the amount and diffusivity of hydrogen on HE % was confirmed. The beneficial effect of Mo2 C addition has been confirmed.