Effect of grain size on the threshold stress intensity factor in fatigue of a ferritic steel

Masounave, Jacques; Baflon, J.-P.

doi:10.1016/0036-9748(76)90142-3

Cited by 149 publications

(32 citation statements)

References 7 publications

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“…[F][L] −2 . This is in agreement with the common interpretation of the crack-size effects on the fatigue threshold at the small scales based on the well-known Hall-Petch law (Verhoeven 1975;Masounave and Bailon 1976). In fact, the crack length can be considered as proportional to the average grain size of the material microstructure and we have ∆K th ∝ d grain .…”

Section: A Unified Fractal Model For the Interpretation Of The Crack-supporting

confidence: 79%

A unified fractal approach for the interpretation of the anomalous scaling laws in fatigue and comparison with existing models

Carpinteri

Paggi

2009

Int J Fract

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In this paper, a critical reexamination of the fractal models for the analysis of crack-size effects in fatigue is proposed. The enhanced ability to detect and measure very short cracks has in fact pointed out the so-called anomalous behavior of short cracks with respect to their longer counterparts. The cracksize dependencies of both the fatigue threshold and the Paris' constant C are only two notable examples of these anomalous scaling laws. In this context, a unified theoretical model seems to be missing and the behavior of short cracks can still be considered as an open problem. A new generalized theory based on fractal geometry is herein proposed, which permits to consistently interpret the short crack-related anomalous scaling laws within a unified theoretical framework. The proposed model is used to interpret relevant experimental data related to the crack-size dependence of the fatigue threshold in metals. As a main result, the model gives an explanation to the experimentally observed variability in the slope of the asymptote of the scaling law for the fatigue threshold in the short crack regime.

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Section: A Unified Fractal Model For the Interpretation Of The Crack-supporting

confidence: 79%

A unified fractal approach for the interpretation of the anomalous scaling laws in fatigue and comparison with existing models

Carpinteri

Paggi

2009

Int J Fract

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“…The coincidence of high threshold stress intensity and large prior austenite grain size in Fe/2Si/0.le OFM (IQ) is consistent with the general, but not universal [24], trend of increased grain size giving higher fatigue thresholds in steels [14,17,25,26]. The significance of the prior austenite grain …”

Section: -14 -supporting

confidence: 61%

Effects of microstructure on fatigue crack growth in duplex ferrite-martensite steels

Wasynczuk

Ritchie

Thomas

1984

Materials Science and Engineering

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Monotonic tensile and fatigue crack growth tests have been performed on AISI 1018 and Fe/2Si/l).lC steels with duplex ferrite-martensite (DFM) microstructures. The effects of microstructure on ambient temperature mechanical properties were examined. Two distinct martensite distributions were produced in AISI 1018 DFM. The primary differences between the two were the ferrite and martensite particle sizes. It was found that tensile fracture was sensitive to both martensite distribution and volume fraction. For a given volume fraction of martensite, large particle sizes increased strength but drastically reduced ductility.Threshold stress intensity ranges for fatigue crack growth in AISI 1018 DFM were found to be unaffected by the distribution or the volume fraction of martensite • -5 -3 / However, crack growth rates in the range of 10 to 10 mm cycle were increased in AISI 1018 DFM when the particle sizes were large. The increased crack growth rates were attributed to a crack extension mechanism involving cleavage fracture in ferrite. The Fe/2Si/0.1C DFM alloy was found to have a considerably higher fatigue threshold stress intensity than AISI 1018 DFM of comparable strength. The -2 -greater near-threshold fatigue crack propagation resistance in Fe/2Si/O.le DFM was attributed to a meandering crack path, generated by the coarser microstructure in this steel, which promotes roughness-induced crack closure and crack deflection effects.

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“…Such microstructural effects on cyclic crack advance are found to be most significant in the nearthreshold regime, below typically ~ 10-6 mm/cycle, where stress intensity levels approach the threshold stress intensity range, 6K o ' for no * detectable growth of long cracks (see refs. [1][2][3][4][5].…”

Section: Introductionmentioning

confidence: 99%

Fatigue crack propagation in dual-phase steels: Effects of ferritic-martensitic microstructures on crack path morphology

1984

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LBL-16264Characteristics of fatigue crack propagation in dual-phase steels have been investigated in a high purity Fe-2Si-0.lC steel with the objective of developing ferritic-martensitic microstructures with maximum resistance to fatigue crack extension whilst maintaining high strength levels. A wide range of crack growth rates has been examined, from ~ 10-8 to 10-3 mm/cycle, in a series of duplex microstructures of comparable yield strength and prior austenite grain size where intercritical heat-treatments were used to vary the proportion, morphology and distribution of the ferrite and martensite phases. Results of fatigue crack propagation tests, conducted on "long cracks" in room temperature moist air environments, revealed a very large influence of microstructure over the entire spectrum of growth rates at low load ratios. Similar trends were observed at high load ratio, although the extent of the microstructural effects on crack growth behavior was V. B. DUTTA is Graduate Student Research

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Effect of grain size on the threshold stress intensity factor in fatigue of a ferritic steel

Cited by 149 publications

References 7 publications

A unified fractal approach for the interpretation of the anomalous scaling laws in fatigue and comparison with existing models

A unified fractal approach for the interpretation of the anomalous scaling laws in fatigue and comparison with existing models

Effects of microstructure on fatigue crack growth in duplex ferrite-martensite steels

Fatigue crack propagation in dual-phase steels: Effects of ferritic-martensitic microstructures on crack path morphology

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