Studies using negative secondary ion mass spectrometry:

Shvachko, V. I.

doi:10.1016/s0039-6028(98)00404-x

Cited by 9 publications

(3 citation statements)

References 11 publications

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“…6): the shape of the curve for cations H + did not change after holding but, for anions [4-, the slope of the linear part of the curve decreased sharply for high densities of the primary current J0. We established that this change is attributable to a decrease in the concentration of diffusing hydrogen [ 14]. …”

Section: Resultsmentioning

confidence: 87%

“…Intensive emission of secondary ions H-from hydrogenated specimens of steel and the linear part of the curve Jsec = f(Jsec) observed for them indicate the relation between the current of ions H-and the volume concentration of hydrogen. Moreover, the time variation in the slope of the linear part illustrates a change in the hydrogen concentration due to diffusion and its further desorption from the surface [14]. Comparing the electronic work function of an iron surface with the electron affinity of a hydrogen atom and also analyzing the conditions of electron exchange during dislodging of secondary ions, we established that hydrogen forms a layer of anions on the atomically pure surfaces of a submicrocrack.…”

Section: Experimental Substantiation Of the Modelmentioning

confidence: 84%

“…We carried out mechanical tests with the help of an improved method [12]. To estimate the influence of hydrogen on mechanical characteristics of steels, we used new, physically grounded criteria [13] and applied secondary-ion mass spectrometry for analysis of the interaction of hydrogen with iron at the atomic level [14]. This gave us the possibility to study complex physical phenomena and reversible hydrogen embrittlement among them.…”

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confidence: 99%

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Reversible hydrogen embrittlement of steels as a physical phenomenon

Shvachko¹

1999

Mater Sci

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Reversible hydrogen embrittlement of structural steels results in serious technological problems, but the physical nature of this complex phenomenon has been insufficiently studied. We present new ideas on its mechanism and use fundamental concepts of the modem physics of metals, literature data, and results of our experiments with specimens made of St3 steel, 09G2S low-carbon steel, and a low-alloyed high-strength steel of type AB to substantiate these ideas. We show that plastic strain causing the appearance of incipient cracks in a metal is a necessary condition for development of reversible hydrogen embrittlement. Hydrogen, having a high diffusive mobility, is transported by moving dislocations to the places of crack initiation in the course of plastic deformation. The physical reason for the embrittling influence of hydrogen consists in the decrease in the critical stress necessary for the loss of stability of incipient microcracks and the transition to their autocatalytic propagation. The new ideas enable us to explain the established regularities of reversible hydrogen embrittlement and can also serve as a basis for further investigations of this phenomenon and the development of methods for its prevention.The harmful action of hydrogen on the mechanical properties of steels is well known [1][2][3][4][5][6][7][8]. At present, anxiety is caused by the formation of flakes and exfbliations in forgings and profile forge-rollings, welding cold cracks induced by hydrogen, development of hydrogen stress corrosion of main pipelines, and hydrogen fracture of equipment in chemical and petrochemical industry and other branches of modem and future engineering. Even a simple enumeration of the existing problems related to hydrogen demonstrates that the investigation of its effect on steel remains topical [9].The forms of manifestation of the negative action of hydrogen on properties of steel are very diverse. In [8], Kolachev proposed a classification of the types of hydrogen embrittlement. Among them, reversible hydrogen embrittlement attracts the highest attention from the scientific and applied viewpoints. Only reversible hydrogen embrittlement is considered to be "true" [10], and, therefore, it was studied in most detail. Various hypotheses and theoretical concepts of the mechanism of reversible hydrogen embrittlement have been proposed and analyzed in numerous works (see, e.g., [2,5,6,8]).The very fact of existence of numerous hypotheses shows that this phenomenon has not yet obtained a convincing and complete explanation. "White spots" in the mechanism of the action of hydrogen complicate the study, prediction, and development of methods for prevention of this process. For this reason, it is necessary to further investigate reversible hydrogen embrittlement, in order to understand it completely, from the beginning to the end [11].In this work, we describe new ideas on the physical nature of reversible hydrogen embrittlement. They are based on fundamental concepts of the modem physics of metals, which describe mec...