Zone of fatique crack growth of stainless steel: Structure-phase states evolution

S. V. Vorob'ev, A. V. Gromova, Yu F. Ivanov, S. V. Konovalov, K. D. Lukin

Результат исследований: Материалы для книги/типы отчетовМатериалы для конференции

Аннотация

The transmission electron microscopy was used to analyze formation of the structural phase states in the fatigue crack growth area in 08X18N10T austenite (0,1%C; 17,5%Cr; 10%N; 1%Ti) stainless steel subjected to highcycle fatigue. In the initial state up to 75% of the total volume was occupied by a chaotic dislocation substructure, the rest was shared in equal proportion by reticular and cellular-reticular substructures. Average scalar density of dislocations amounted to 1.5.1010cm-2. Carbide phase was represented by chromium carbides M23C6 sized 0.1-1 μm comprised of (FeCr)23C6 and TiC with average size of 62±5 nm. High-cycle fatigue testing resulted in higher (up to 5.2 *1010cm-2) scalar density of dislocations in the ruptured zone which increased share of material in the total volume with ordered dislocation substructures against the chaotic ones. In steel fractured after 170 thousand stress cycles the fatigue growth area has the following proportion of dislocation substructures: chaotic - 5%, reticular - 70%, cells and balls comprise the rest in equal proportion. In strained steel stacking faults and microtwins are formed, channels for slip and twinning steel deformation are triggered. Deformation twinning leads to martensite γ→ε transformation. Steel fatigue loading entails partial dissolution of carbides M23C6 near grain boundaries and isolation of Cr3C2 on carbide interlayer boundaries, as well as coagulation of TiC particles up to 120±7 nm in ruptured state. At the same time their size variety is substantially expanded. Microcracks form near carbide-matrix phase boundaries and within the volume of carbide phase particles that are some nanometers in size. Such locations are stress concentrators which lead to failure of the whole sample.

Язык оригиналаАнглийский
Название основной публикацииAdvances in Heterogeneous Material Mechanics 2008 - Proceedings of the 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008
Страницы435
Число страниц1
СостояниеОпубликовано - 2008
СобытиеAdvances in Heterogeneous Material Mechanics 2008 - 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008 - Huangshan, Китай
Продолжительность: 3 июн 20088 июн 2008

Другое

ДругоеAdvances in Heterogeneous Material Mechanics 2008 - 2nd International Conference on Heterogeneous Material Mechanics, ICHMM 2008
СтранаКитай
ГородHuangshan
Период3.6.088.6.08

ASJC Scopus subject areas

  • Materials Science (miscellaneous)
  • Materials Chemistry

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