PSI - Issue 60

Gopal Sanyal et al. / Procedia Structural Integrity 60 (2024) 311–323 Author name / StructuralIntegrity Procedia 00 (2019) 000–000

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(Robertson et. al., 2015). In this course, interstitial hydrogen lowers the stress required for metal atoms to fracture by reducing the cohesive energy. It can occur when the local concentration of hydrogen is high, such as due to the increased hydrogen solubility in the tensile stress field at a crack tip, at stress concentrators, or in the tension field of edge dislocations. 4. Conclusions In-situ mechanical testing of Cr-Mo-V-Ni steel for RPV application in terms of tensile propertiesand fracture toughness has been found to manifest loss of ductility due to hydrogen embrittlement. While the yield and flow stress are not affected the tensile fracture strain and reduction of area are significantly affected. The necking is largely suppressed in the tensile test carried out under electrochemical in-situ charging. The crack tip opening and plasticity is absent in the initiation of crack on exposure to continuous high fugacity hydrogen. There is significant drop in the initiation fracture toughness of the Cr-Mo-V-Ni steel. The failure mode has been found to switch from ductile to brittle while compared with test results for samples tested in air. The underlying mechanism for such observation has been hypothesized to be related to hydrogen induced de-cohesion. Acknowledgements The authors acknowledge the keen interest shown of Dr. R. Tewari (Associate Director, Materials Group, BARC) in the work. ASTM E 8M-01, (American Standard Test Method) Standard test methods for tension testing of metallic materials, West Conshohocken PA: ASTM; 2001. ASTM E 1820-01, (American Standard Test Method) Standard test method for measurement of fracture toughness, West Conshohocken PA: ASTM; 2001. Birnbaum H K, Sofronis P, 1994, Hydrogen-enhanced local palsticity - a mechanism for hydrogen-related fracture, Mater Sci Engg A 176 pp 191-202. Bogaerts, W., MacDonald, D., Jovanovic, A., Zheng, J., Dockx, K. 2017, Hydrogen cracks in Belgian nuclear Reactor Pressure Vessels: Five years after their discovery - An update. In NACE - International Corrosion Conference Series 7, pp. 4661?4669. Briant, C. L., and S. K. Banerji. 1978Intergranularfailure in steel: the role of grain-boundary composition. International metals reviews 23, no. 1 pp 164-199. Bockris J. O'M., McBreen J., Nanis L., 1965 The hydrogen evolution kinetics and hydrogen entry into alpha-Iron, J. Electrochem Soc., 112 pp 1025 - 1031. Davies, L. M. 1999, A comparison of western and eastern nuclear reactor pressure vessel steels. International journal of pressure vessels and piping 76, no. 3 pp 163-208. Gabetta G, Cioffi P., Bruschi R., 2018 Engineering thoughts on hydrogen embrittlement, IGF Workshop Fracture and Structural Integrity , Procedia Structural Integrity 9 pp 250-256. Gabrielli, C., Maurin, G., Mirkova, L., Perrot H., 2006 , Transfer function analysis of hydrogen permeation through a metallic membrane in a Devanathan cell part II: Experimental investigation on iron membrane, Electroanal. Chem., 590 pp 15 - 25. Gupta C K, 2001, Nuclear Reactor Materials, In Encyclopedia of Materials: Science and Technology (Eds.) Buschow K H J, R W .Cahn, Flemings M C, B Ilshner, Kramer E J, S Mahajan, Veyssiere P, Pergamon, Elsevier, USA pp 6339 ・ 6349. Gupta, C., J. K. Chakravartty, and S. Banerjee., 2010, Dynamic Strain Aging in New Generation Cr-Mo-V Steel for Reactor Pressure Vessel Applications, Metallurgical and Materials Transactions A 41, no. 13 pp 3326-3339. Hillier E. M. K., Robinson, M. J., 2004, Hydrogen embrittlement of high strength steel electroplated with zinc-cobalt alloys, Corros. Sci., 46 pp 715 - 727. Loidl, M., Kolk, O., Gobel, T., 2011 Characterisation of hydrogen embrittlement in automotive advanced high strength steels Mat-wiss u. Werksstofftech 42 No.12 pp 1105 - 1110. References

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