TY - GEN
T1 - Hydrogen-induced ductility loss in cast irons
AU - Usuda, T.
AU - Matsuno, K.
AU - Matsunaga, H.
AU - Yanase, K.
AU - Endo, M.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2013
Y1 - 2013
N2 - The effect of hydrogen-charging was investigated with respect to the tensile properties ofthree types of ductile cast irons: JIS FCD400, FCD450 and FCD700. In this study, hydrogen chargingled to a marked ductility loss in all the ductile cast irons. The thermal desorption spectroscopy and thehydrogen microprint technique revealed that, in the hydrogen-charged specimens, most of solutehydrogen was diffusive and mainly segregated at the graphite, the graphite/matrix interface zone andthe pearlite. In the fracture process of the non-charged specimen, the neighboring graphites wereinterconnected with each other mainly by ductile dimple fracture. On the other hand, in the fractureprocess of the hydrogen-charged specimen, the graphites were interconnected by cracks. Thedifference in the fracture morphology between the non-charged and the hydrogen-charged specimensis attributed to the presence of diffusive hydrogen in graphite and graphite/matrix interface. Duringearly stage of fracture process in hydrogen-charged specimen, the interspace between graphite andmatrix is filled with hydrogen gas, which leads to the ductility loss of matrix in the vicinity of graphite.Even after the initiation of crack from graphite, hydrogen is continuously outgassed from graphite andsupplied to the crack tip. Therefore, concerning the effect of hydrogen on the strength of cast irons, arole of subsurface graphite as a "local hydrogen supplier" should be taken into consideration.
AB - The effect of hydrogen-charging was investigated with respect to the tensile properties ofthree types of ductile cast irons: JIS FCD400, FCD450 and FCD700. In this study, hydrogen chargingled to a marked ductility loss in all the ductile cast irons. The thermal desorption spectroscopy and thehydrogen microprint technique revealed that, in the hydrogen-charged specimens, most of solutehydrogen was diffusive and mainly segregated at the graphite, the graphite/matrix interface zone andthe pearlite. In the fracture process of the non-charged specimen, the neighboring graphites wereinterconnected with each other mainly by ductile dimple fracture. On the other hand, in the fractureprocess of the hydrogen-charged specimen, the graphites were interconnected by cracks. Thedifference in the fracture morphology between the non-charged and the hydrogen-charged specimensis attributed to the presence of diffusive hydrogen in graphite and graphite/matrix interface. Duringearly stage of fracture process in hydrogen-charged specimen, the interspace between graphite andmatrix is filled with hydrogen gas, which leads to the ductility loss of matrix in the vicinity of graphite.Even after the initiation of crack from graphite, hydrogen is continuously outgassed from graphite andsupplied to the crack tip. Therefore, concerning the effect of hydrogen on the strength of cast irons, arole of subsurface graphite as a "local hydrogen supplier" should be taken into consideration.
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U2 - 10.4028/www.scientific.net/MSF.750.260
DO - 10.4028/www.scientific.net/MSF.750.260
M3 - Conference contribution
AN - SCOPUS:84875856313
SN - 9783037856604
T3 - Materials Science Forum
SP - 260
EP - 263
BT - Advanced Materials Science and Technology
PB - Trans Tech Publications Ltd
T2 - 8th International Forum on Advanced Materials Science and Technology, IFAMST 2012
Y2 - 1 August 2012 through 4 August 2012
ER -