Structure and phase composition behavior in multicycle fatique of quenched carbon steel

V. E. Gromov, O. V. Sosnin, Yu F. Ivanov, E. V. Kozlov

Research output: Chapter in Book/Report/Conference proceedingConference contribution

Abstract

The defect substructure and phase composition evolution of quenched 60GS2 (0,6%C, 1%Mn, 2%Si) steel are studied by transmission diffraction electron microscopy. Quenching the steel leads to the formation of a mixed packet-plate martensite structure containing around 8-10% residual austenite. The mean transverse dimensions of the plate and packet martensite crystals are 242±11 nm and 180±10 nm, respectively. Fatigue loading of steel with Ni=1,2·105 cycles leads to the formation of subgrains, whose relative content is around 44%. The mean size of the anisotropic subgrains is 1,150±0,025 μ. Increasing the number of loading cycles to N 2=1,46·105 (failure) increases the subgrain content to around 75% and increases their mean size to 1,70±0,03 μm. Within the subgrains, there is a tangled-network dislocational structure. The scalar dislocation density is 2,8·1010cm-2. Cementite particles are distributed along the subgrain boundaries and at their junctions, as a rule. At the intermediate stage of loading, the cementite particles take the form of layers, while the failured sample tends to have globular morphology. In the intermediate stage of fatigue loading Ni displacement of the largeangle grain boundaries is observed, indicating dynamic recrystallization of the material. This process is accompanied by the formation of regions characterized by high elastic stress fields and a large quantity of cementite particles at the boundary junctions. Increasing the number of loading cycles to around 1,46·105 is accompanied by further tempering of these volumes of the material, with the formation of a two-phase martensite-austenite structure. Repeated martensitic transformation is sometimes also observed in inhomogeneous packets. In this case, the newly formed martensite crystals lie parallel to the initial martensite crystals.

Original languageEnglish
Title of host publicationAdvances in Heterogeneous Material Mechanics 2008 - Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008
Pages434
Number of pages1
Publication statusPublished - 2008
EventAdvances in Heterogeneous Material Mechanics 2008 - 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008 - Huangshan, China
Duration: 3 Jun 20088 Jun 2008

Other

OtherAdvances in Heterogeneous Material Mechanics 2008 - 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008
CountryChina
CityHuangshan
Period3.6.088.6.08

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Keywords

  • Carbon steel
  • Fatigue
  • Martensite

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Materials Chemistry

Cite this

Gromov, V. E., Sosnin, O. V., Ivanov, Y. F., & Kozlov, E. V. (2008). Structure and phase composition behavior in multicycle fatique of quenched carbon steel. In Advances in Heterogeneous Material Mechanics 2008 - Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008 (pp. 434)