QUANTITATIVE EVALUATION OF HYDROGEN MICRO-DAMAGE IN 316L AUSTENITIC STAINLESS STEEL

摘要

In this paper an evaluation is made, by means of quantitative fractography and image analysis techniques, of the hydrogen-assisted micro-damage in axisymmetric notched samples of 316L austenitic stainless steel subjected to hydrogen embrittlement tests. Such a micro-damage created by hydrogen is concentrated in a external circumferential ring with the same centre as the cross sectional area of the notched samples. The microscopical appearance of this embrittled zone or damaged area is very rough and irregular at the micro-scale, with evidence of secondary cracking, in contrast with the smooth surface (at the micro-scale) created by micro-void coalescence {dimpledfracture) in the inner core which is not embrittled by hydrogen and fails by mechanical reasons. In addition, differences are observed in the matter of the appearance of the hydrogen-assisted micro-damage area as a function of the notched geometry and of the embrittlement time.