Grain boundary embrittlement of the iron-base superalloy IN903A

Bricknell, R.H.; Woodford, D. A.

doi:10.1007/bf02643573

Cited by 76 publications

(22 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The PFZ is enriched in Cr, which improves the oxidation resistance of the near grain boundary region. A similar beneficial effect of Cr on environmental crack growth resistance has also been observed for other high-temperature alloys ( Ref 11,[26][27][28][29][30][31]. There is, however, at least one report of an improvement in static crack growth for alloy X-750, where the formation of M 23 C 6 resulted in lean Cr from the PFZ.…”

Section: Environmental Effectsupporting

confidence: 51%

Effect of Microstructure and Environment on Static Crack Growth Resistance in Alloy 706

Yang¹,

Hawk²,

Duquette

et al. 2009

J. of Materi Eng and Perform

View full text Add to dashboard Cite

The relationship between thermo-mechanical processing, resultant microstructure, and mechanical properties has been of interest in the field of metallurgy for centuries. In this work, the effect of heat treatment on microstructure and key mechanical properties important for turbine rotor design has been investigated. Specifically, the tensile yield strength and crack growth resistance for a nickel-iron based superalloy 706 has been examined. Through a systematic study, a correlation was found between the processing parameters and the microstructure. Specifically, differences in grain boundary and grain interior precipitates were identified and correlated with processing conditions. Further, a strong relationship between microstructure and mechanical properties was identified. The type and orientation of grain boundary precipitates affect time-dependent crack propagation resistance, and the size and volume fraction of grain interior precipitates were correlated with tensile yield strength. It was also found that there is a strong environmental effect on time-dependent crack propagation resistance, and the sensitivity to environmental damage is microstructure dependent. Microstructures with g decorated grain boundaries were more resistant to environmental damage through oxygen embrittlement than microstructures with no g phase on the grain boundaries. An effort was made to explore the mechanisms of improving the timedependent crack propagation resistance through thermo-mechanical processing, and several mechanisms were identified in both the environment-dependent and the environment-independent category. These mechanisms were ranked based on their contributions to crack propagation resistance.

show abstract

Section: Environmental Effectsupporting

confidence: 51%

Effect of Microstructure and Environment on Static Crack Growth Resistance in Alloy 706

Yang¹,

Hawk²,

Duquette

et al. 2009

J. of Materi Eng and Perform

View full text Add to dashboard Cite

show abstract

“…While many aspects have been addressed there remains a lack of understanding of the detailed effects of oxygen interaction in the crack tip region, mainly due to experimental difficulties of such analyses. For the two most prominent proposed degradation mechanisms, the oxygen interaction is believed to occur on the nanometre-scale for the mechanism termed dynamic embrittlement [7] and on the scale of tens of microns for strain assisted grain boundary oxidation (SAGBO) [8]. The ability to target the correct area and perform sample preparation with minimal introduction of artefacts is crucial.…”

Section: Introductionmentioning

confidence: 99%

Oxygen influenced intergranular crack propagation: analysing microstructure and chemistry in the crack tip region

Viskari¹,

Johansson²,

Stiller³

2011

Materials at High Temperatures

View full text Add to dashboard Cite

Ni-base superalloys have for decades been studied with regard to environmentally influenced intergranular crack propagation. For high temperature fatigue frequencies 50.1 Hz, it has been shown that an oxygen-rich environment promotes time-dependent crack growth while at 40.1 Hz andyor in inert environments (e.g. vacuum) crack growth is cycle dependent. Oxygen interaction at, or ahead of, the crack tip has been pointed out as the reason for the degraded mechanical properties. While many aspects of this type of crack growth have been previously investigated there is still no consensus about the detailed mechanisms, mainly due to the lack of in-detail investigations of the crack-tip region.Here, crack tip regions in the Ni-base superalloy Alloy 718 were studied. Specimens were subjected to 90 s hold-times at 550 C and 650 C. Crack growth was arrested before final fracture, allowing cross-sectional analyses of the crack-tip region using scanning electron microscopy (SEM). Detailed studies of the crack-tip region were performed using transmission electron microscopy (TEM) and atom probe tomography (APT). For both APT and TEM samples, site-specific focussed ion beam (FIB) sample preparation was performed in a combined FIB-SEM system. The methodology of accessing and analysing the crack tip region is shown. Initial results on oxidation, oxygen penetration and plastic deformation are shown and discussed.

show abstract

“…The effect of oxygen on intergranular fracture has been extensively investigated in many alloys, especially with high temperature mechanical tests (72)(73)(74)(75)(76). Grain boundary diffusion of oxygen in addition to oxidation is assumed to accelerate this oxygeninduced intergranular embrittlement.…”

Section: Microstructurementioning

confidence: 99%

Study of intergranular embrittlement in Fe-12Mn alloys

Lee¹

1982

View full text Add to dashboard Cite

Grain boundary embrittlement of the iron-base superalloy IN903A

Cited by 76 publications

References 8 publications

Effect of Microstructure and Environment on Static Crack Growth Resistance in Alloy 706

Effect of Microstructure and Environment on Static Crack Growth Resistance in Alloy 706

Oxygen influenced intergranular crack propagation: analysing microstructure and chemistry in the crack tip region

Study of intergranular embrittlement in Fe-12Mn alloys

Contact Info

Product

Resources

About