Effect of hetero- and homo-nanostructure on the hydrogen embrittlement resistance in heavily deformed 316LN austenitic stainless steel

Abstract

The heterogeneous and homogeneous nanostructured 316LN austenitic stainless steel with tensile strengths of approximately 1.8 and 2.0 GPa were fabricated by 92% heavy cold rolling and high-pressure torsion straining, respectively. The influence of heterogeneous and homogenous nanostructures on the resistance to hydrogen embrittlement was investigated. Thermal desorption spectroscopy of the electrochemical hydrogen-charged specimen showed that both nanostructures exhibited almost the same concentration of diffusible hydrogen. While the tensile properties of the homogenous nanostructure were severely affected by the diffusible hydrogen, it had less impact on the tensile properties of the heterogeneous nanostructure. The difference in the embrittlement behavior between the heterogeneous and homogeneous nanostructures is attributed to the mechanism of crack growth observed by tensile fractography. Hydrogen embrittlement is suppressed in the heterogeneous nanostructure because crack growth is hindered by twin domains. The crack easily initiates in the homogeneous nanostructure and the resistance to crack growth is low.

Hydrogen Cooling of Turbo Aggregates and the Problem of Rotor Shafts Materials Degradation Evaluation

“…The presence of inclusions and nanostructures can increase the hydrogen resistance and fracture toughness of steel [78][79][80]. For example, chemical heterogeneity in highstrength steel can significantly increase fracture resistance and ductility in hydrogencontaining environments [78].…”

“…For example, chemical heterogeneity in highstrength steel can significantly increase fracture resistance and ductility in hydrogencontaining environments [78]. The effect of heterogeneous and homogeneous nanostructures on the resistance to hydrogen embrittlement in steel [79] in a thermodynamic-based model to analyze hydrogen capture at the inclusion-matrix interface showed its dependence on the strength of the steel matrix [80]. An examination of the effect of sulfide inclusions on the mechanical properties of steel showed that inclusions have a detrimental effect on fatigue resistance [81].…”

“…To illustrate the significance of hydrogen s influence on the steel properties, a symbol with hydrogen is shown in the central part of the figure. Studies have shown that the presence of inclusions and nanostructures can affect steel-strength characteristics [78][79][80].…”

“…A particle of degraded material that was separated from the rotor shaft as a result of the intensification of destructive processes caused by the complex action of aging factors Studies have shown that the presence of inclusions and nanostructures can affect steel-strength characteristics [78][79][80].…”