Sulfur-induced dynamic embrittlement in a low-alloy steel

Bika, D.; Pfaendtner, J.A.; Menyhárd, M.; McMahon, C.J.

doi:10.1016/0956-7151(94)00388-x

Cited by 89 publications

(57 citation statements)

References 18 publications

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“…Figure 1 illustrates schematically this kind of time-dependent damage mechanism. Dynamic embrittlement was shown to cause intergranular failure for several alloys and different embrittling species in earlier studies, e.g., sulfur-induced cracking of alloy steels 13 , tin-induced cracking of Cu-Sn alloys 14 and oxygen-induced cracking of a Cu-Be alloy 15 , of a Ni-Mo-Cr alloy 16 , and of the intermetallic alloy Ni 3 Al…”

Section: Dynamic Embrittlementmentioning

confidence: 99%

Oxygen-induced intergranular fracture of the nickel-base alloy IN718 during mechanical loading at high temperatures

et al. 2004

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There is a transition in the mechanical-failure behavior of nickel-base superalloys from ductile transgranular crack propagation to time-dependent intergranular fracture when the temperature exceeds about 600 °C. This transition is due to oxygen diffusion into the stress field ahead of the crack tip sufficient to cause brittle decohesion of the grain boundaries. Since very high cracking rates were observed during fixed-displacement loading of IN718, it is not very likely that grain boundary oxidation governs the grain-boundary-separation process, as has been proposed in several studies on the fatigue-damage behavior of the nickel-base superalloy IN718. Further studies on bicrystal and thermomechanically processed specimens of IN718 have shown that this kind of brittle fracture, which has been termed "dynamic embrittlement", depends strongly on the structure of the grain boundaries.

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Section: Dynamic Embrittlementmentioning

confidence: 99%

Oxygen-induced intergranular fracture of the nickel-base alloy IN718 during mechanical loading at high temperatures

et al. 2004

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“…Regarding the time dependent part, it has been seen in many studies, cf. [18,32,54] and Paper III, that for sustained load crack growth it takes some time to reach the stabilised growth rate value. As a result, it was proposed that the growth rate itself should depend on the damaged zone length, unlike traditional models which assumes fully developed growth rates from the beginning (see the previous chapter).…”

Section: Brief Model Outlinementioning

confidence: 99%

“…oxygen) weaken the grain boundaries, and allow for further crack advancement, see e.g. [18,22,32]. SAGBO involves oxidation of grain boundaries and the subsequent cracking of these oxides, allowing for further crack advancement, see e.g.…”

Section: Damage Theoriesmentioning

confidence: 99%

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High Temperature Fatigue Crack Growth in a Ni-based Superalloy : Modelling Including the Interaction of Dwell Times

Storgärds¹

2015

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Safe life of gas turbines is always of major concern for manufacturers in order to ensure passenger safety and stable continuous power output. An increasing amount of resources have been put into research and development to assure that all safety aspects are covered in the design of new turbines and to ensure that enough frequent service intervals are scheduled to avoid complications. Many of these issues require good knowledge of material properties and of how to use these in the design process. Some of these relate to fatigue which is of major concern in all parts of a development programme. However, while some fatigue problems have been extensively studied, some have not. One example is crack growth with influence of dwell times at elevated temperature in combination with cyclic loading. Such loading conditions have been shown to give a different cracking behaviour compared to rapid cyclic loading, increasing the growth rate significantly with respect to the number of load cycles. Improved models for predicting this behaviour is therefore of major interest for gas turbine manufacturers, and could substantially increase the reliability. As a result, more research is needed in order solve these problems. The work presented in this dissertation has focused on how to predict life under the above-mentioned circumstances. The materials used in high temperature gas turbine applications are often nickel-based superalloys, and in this work the most common one, Inconel 718, has been studied. Mechanical experiments have been performed under operation like conditions in order to receive material data for the subsequent modelling work. The modelling approach was chosen such that the underlying physics of the dwell time cracking have been incorporated on a phenomenological basis, creating a model which can be physically motivated as well as used for industrial applications. The main feature of the modelling work has been to track material damage which is received from dwell times, how this interacts with cyclic loading and how it affects the crack growth rate, thus creating a load history dependent model. The outcome of this work has resulted in a model which is both easy to use and which has shown to give good correlation to available experimental data. Key components such as calibration for cheap and easy parameter determination, validation on complex engine spectra loadings, three dimensional crack growth, overload influences, material scatter, thermo-mechanical fatigue crack growth and the impact of high cycle fatigue loadings, are all covered in the presented work, both as experimental findings and as continuous development of the modelling concept. The dissertation consists of two parts. In the first an introduction with the theory and background to crack growth with dwell times is given, while the second part consists of 10 papers

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“…[7][8][9] On the other hand, lots of studies have supported that the segregation of impurities (especially, phosphorus) to the PAGBs causes the intergranular cracking by lowering the cohesive grain boundary strength. [10][11][12][13][14][15][16][17][18][19][20][21][22][23] The T/ P23 heat-resistant steel (2.25Cr1.5WVNb) has been known to show a high susceptibility to the reheat cracking. Meanwhile, the T/P92 heat-resistant steel (9Cr1.5W0.5MoVNb) is not susceptible to the reheat cracking.…”

Section: Introductionmentioning

confidence: 99%

Difference in Reheat Cracking Susceptibility of 2.25Cr-W and 9Cr-W Heat-resistant Steels

2017

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Sulfur-induced dynamic embrittlement in a low-alloy steel

Cited by 89 publications

References 18 publications

Oxygen-induced intergranular fracture of the nickel-base alloy IN718 during mechanical loading at high temperatures

Oxygen-induced intergranular fracture of the nickel-base alloy IN718 during mechanical loading at high temperatures

High Temperature Fatigue Crack Growth in a Ni-based Superalloy : Modelling Including the Interaction of Dwell Times

Difference in Reheat Cracking Susceptibility of 2.25Cr-W and 9Cr-W Heat-resistant Steels

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