Crack growth under constant sustained load at elevated temperature in IN718 superalloy

Branco, C.M.; Baptista, Joana; Byrne, J.

doi:10.3184/096034099783641227

Cited by 9 publications

(11 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The influence of specimen geometry was also observed in sustained load tests of Inconel 718 at 600 °C 4 . The results obtained showed an acceleration of crack growth in the CT specimens in comparison with the CC specimens.…”

Section: Introductionmentioning

confidence: 81%

Influence of stress state on high temperature fatigue crack growth in Inconel 718

Antunes

Ferreira

Branco

et al. 2001

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

The influence of stress state on fatigue crack growth in nickel‐base superalloys at high temperature is considered, based on studies in corner crack specimens of Inconel 718 at 600 °C. At high frequency and low R, cycle‐dependent trans‐granular crack growth occurs along the whole crack front, and growth rates are similar at the surface and within the interior of specimens, maintaining the original quarter‐circular shape. For conditions of low frequency and high R, increased crack growth rate per cycle is observed with the crack tunnelling ahead at the centre. A time‐dependent intergranular crack propagation mode occurs in the plane strain interior, attributed to an oxidation mechanism, whereas near the surfaces under plane stress, a trans‐granular cyclic plasticity mechanism is observed. It is proposed that in addition to frequency and R, that stress state influences the competition between the mechanisms controlling crack growth and the transition between them: plane strain in the interior favouring an oxidation‐controlled intergranular cracking mechanism as compared with the plane stress surfaces where cyclic plasticity dominates. An FEM study suggests that this influence of stress state is not associated with variation of ΔK along the crack front.

show abstract

Section: Introductionmentioning

confidence: 81%

Influence of stress state on high temperature fatigue crack growth in Inconel 718

Antunes

Ferreira

Branco

et al. 2001

Fatigue Fract Eng Mat Struct

Self Cite

View full text Add to dashboard Cite

show abstract

“…Such behaviour, is generally more pronounced under conditions resulting in intergranular cracking [18][19][20][21]. Branco et al [19] observed that during sustained load crack propagation tests the introduction of side grooves, which enhance the plane strain condition of CT-specimens, increase the time dependent crack propagation rate.…”

Section: Introductionmentioning

confidence: 96%

Anisotropy effects during dwell-fatigue caused by δ-phase orientation in forged Inconel 718

Saarimäki

Colliander

Moverare

2017

Materials Science and Engineering: A

View full text Add to dashboard Cite

A B S T R A C TInconel 718 is a commonly used superalloy for turbine discs in the gas turbine industry. Turbine discs are often subjected to dwell-fatigue as a result of long constant load cycles. The effect of anisotropy on dwell-fatigue cracking in forged turbine discs have not yet been thoroughly investigated. Crack propagation behaviour was characterised using compact tension (CT) samples cut in different orientations from a real turbine disc forging. Samples were also cut in two different thicknesses in order to investigate the influence of plane strain and plane stress condition on the crack propagation rates. The samples were subjected to dwell-fatigue tests at 550°C with 90 s or 2160 s dwell-times at maximum load. Microstructure characterisation was done using scanning electron microscopy (SEM) techniques such as electron channelling contrast imaging (ECCI), electron backscatter diffraction (EBSD), and light optical microscopy (LOM). The forged alloy exhibits strong anisotropic behaviour caused by the non-random δ-phase orientation. When δ-phases were oriented perpendicular compared to parallel to the loading direction, the crack growth rates were approximately ten times faster. Crack growth occurred preferably in the interface between the γ-matrix and the δ-phase.

show abstract

“…The material has been obtained from root sections doi: 10.3184/096034011X13056438123488 MATERIALS AT HIGH TEMPERATURES 28(2) Figure 1 Application of conventionally cast IN-738 LC and coarse grain structure. of turbine blades, which have been hot isostatically pressed.…”

Section: Materials and Experimental Proceduresmentioning

confidence: 99%

“…with Z ¼ ½2 þ 0:522 Á ð1 À ayW Þ for CT-specimens [7] and Z ¼ 1 for CC-specimens [10], the applied load F, the specimen width W, the specimen thickness B and the creep part of the measured load line displacement (LLD) rate ð dvy dtÞ c .…”

mentioning

confidence: 99%

Creep crack behaviour of a coarse grain nickel-base super alloy

Mueller

Scholz

Berger

2011

Materials at High Temperatures

View full text Add to dashboard Cite

The paper presents creep crack growth data, obtained for cast nickel-base super alloy IN-738 LC, which represents a typical large coarse grain structure. Long term creep crack growth experiments were performed at 700 and 850 C on side-grooved compact tension and corner crack specimens. In parallel, uniaxial creep tests on smooth specimens were conducted. The coarse grain structure has been examined using electron backscatter diffraction (EBSD).Creep fracture in polycrystalline materials is observed to be typically intergranular and dominates along grain boundaries. These observations were confirmed for the investigated alloy. From metallographic examinations, an effect of grain orientation on creep crack behaviour, however, was not observed.The Nikbin -Smith -Webster (NSW) model, which is based on the creep fracture mechanics parameter C*, and a damage accumulation model, which considers only nominal stress in the ligament, lead to reasonable results when recalculating creep crack growth.

show abstract

Crack growth under constant sustained load at elevated temperature in IN718 superalloy

Cited by 9 publications

References 0 publications

Influence of stress state on high temperature fatigue crack growth in Inconel 718

Influence of stress state on high temperature fatigue crack growth in Inconel 718

Anisotropy effects during dwell-fatigue caused by δ-phase orientation in forged Inconel 718

Creep crack behaviour of a coarse grain nickel-base super alloy

Contact Info

Product

Resources

About