Hydrogen effects on cyclic deformation behaviour of a low alloy steel

authored by

H. J. Maier, W. Popp, H. Kaesche

Abstract

The effects of absorbed hydrogen with low to intermediate input activity on the fatigue behaviour of a spheroidized low alloy steel were studied. The fatigue tests indicated that the crack growth rate increases monotonically with the hydrogen input activity. Hydrogen gas pressures as low as 10^-5 mbar were found to influence the crack growth rate as compared to ultra-high vacuum. The microstructural studies revealed that the observed increase in fatigue crack growth rate in the presence of hydrogen is a consequence of an increased micro-crack nucleation rate at carbide-ferrite interfaces in the plastic zone ahead of the main crack. Hydrogen swept-in by moving dislocations reduces the cohesive forces at these interfaces. Moreover, transmission electron microscopy and X-ray studies both showed a change in the bulk dislocation arrangement when specimens were cyclically deformed in gaseous hydrogen as a result of hydrogen-enhanced plasticity. This in turns affects the hydrogen transport rate as observed by hydrogen permeation studies.

External Organisation(s)

University of Siegen

Type

Paper

Pages

343-352

No. of pages

10

Publication date

1996

Publication status

Published

Peer reviewed

Yes

ASJC Scopus subject areas

General Engineering