On the dual slope coffin-manson relationship during low cycle fatigue of Ni-base alloy in 718

Bhattacharyya, Arpita; Sastry, G. V. S.; Kutumbarao, V.V.

doi:10.1016/s1359-6462(96)00405-8

Cited by 16 publications

(14 citation statements)

References 12 publications

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“…. The behaviour is similar to those reported earlier by various other researchers for different materials . Sanders et al observed a dual slope in In 718 in the temperature ranging from 477 to 700 K but have not reported any convincing micromechanism leading to this behaviour.…”

Section: Discussionsupporting

confidence: 89%

“…The behaviour is similar to those reported earlier by various other researchers for different materials. [22][23][24][25] Sanders et al 24 observed a dual slope in In 718 in the temperature ranging from 477 to 700 K but have not reported any convincing micromechanism leading to this behaviour. According to Mediratta et al, 27 the bilinear slope in CM plot of dual-phase steels was due to the sheer change in the cyclic strain-hardening coefficient.…”

Section: Discussionmentioning

confidence: 98%

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Micromechanism of cyclic plastic deformation of alloy IN 718 at 600 °C

Banerjee

Sahu

Paulose

et al. 2016

Fatigue Fract Eng Mat Struct

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In the present investigation, an attempt was made to understand the cyclic deformation micromechanism of gas turbine alloy Inconel 718 at 600 °C (i) by conducting low cycle fatigue and creep–fatigue interaction tests and (ii) by studying the microstructure evolution in the material during fatigue tests through extensive electron microscopy. Bilinear slope was obtained in the Coffin–Manson plot for all low cycle fatigue tests, and it was confirmed through transmission electron microscopic examination that microtwinning was the predominant mode of deformation at low plastic strain values, whereas slip and shearing of γ″ precipitates were the predominant mode of deformation at higher plastic strain values. Fatigue life was adversely affected when hold time was introduced at peak tensile strain during creep–fatigue interaction tests. Formation of stepped interface at microtwin boundaries and coarsening of niobium carbide precipitates were observed to be the major microsturctural changes during creep–fatigue interaction tests.

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Section: Discussionsupporting

confidence: 89%

Section: Discussionmentioning

confidence: 98%

Micromechanism of cyclic plastic deformation of alloy IN 718 at 600 °C

Banerjee

Sahu

Paulose

et al. 2016

Fatigue Fract Eng Mat Struct

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“…Therefore, the research on fatigue performance of the Inconel 718 alloy has been widely concerned. According to the specific service environment temperature and load of the parts, it can be roughly divided into several aspects: high temperature [2]/medium temperature [3]/room temperature [4,5] low cycle fatigue, high temperature [6,7]/room temperature [8]/low temperature [9,10] high cycle fatigue, and ultra-high cycle fatigue [11,12] performance. Fournier et al [13] found that the Inconel 718 alloy in the solution treated and aged (ST + A) state had cyclic softening while in the direct aged (DA) state [14] had cyclic hardening under high temperature.…”

mentioning

confidence: 99%

“…The cyclic deformation mechanisms were studied at different temperatures by Sanders et al [16] and Xiao et al [17,18]. As for the relationship between fatigue life and strain amplitude, studies have shown that both ST + A state [19] and DA state [20] Inconel 718 alloys meet the Manson-Coffin relation at high temperatures, while ST + A state [4] alloys and other aged state [15] alloys meet the bilinear Manson-Coffin relation at room temperature. According to the different factors affecting the low-cycle fatigue performance, the influence of microstructure on the low-cycle fatigue life of notch [21] and hot forged alloys [22], the influence of delta phase content [23] and thermal corrosion [24] on low-cycle fatigue behavior, and the influence of frequency and waveform on fatigue crack propagation rate [25] have been studied.…”

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confidence: 99%

High Cycle Fatigue Performance of Inconel 718 Alloys with Different Strengths at Room Temperature

Liqiong

Liang

et al. 2018

Metals

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In this paper, the high cycle fatigue performance of solid solution state and aged Inconel 718 superalloys was studied at room temperature. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were used to analyze the original structural features and fatigue deformation features of two kinds of alloys. SEM, laser scanning confocal microscopy, and electron backscatter diffraction (EBSD) were used to analyze the secondary fracture features of the fatigue fracture morphology and fatigue fracture profile. The results showed that the aging treatment significantly affected the strength and plasticity of the alloy, which in turn affected the fatigue performance of the alloy. After the aging treatment, the yield strength σ s and the tensile strength σ b of the Inconel 718 alloy increased by 152% and 65.9%, respectively, compared with those of the solid solution state, but the rate of elongation δ and rate of contraction in the cross-section area ϕ decreased by 63.7% and 52.3%, respectively. The fatigue limit of the aged state was lower than that of the solid solution state by 6.3%. The quadratic function relationship between the high cycle fatigue limit σ −1 and the tensile strength σ b of the Inconel 718 superalloy at room temperature was σ −1 = σ b · (0.869−3.67 × 10 −4 · σ b ). An analysis of the fatigue fracture mechanism showed that the fatigue fractures before and after aging were all initiated in the grains oriented relatively unfavorably on the surface of the sample, with a mixture of intergranular and transgranular propagation after the transgranular propagation of several grains. The higher plasticity of the solid solution state Inconel 718 alloy resulted in a large number of slip deformation zones under high cycle fatigue loads, and the plastic deformation was relatively uniform. The lengths of the secondary fractures were as high as 120 µm, which formed the single-source plastic fatigue fracture that promoted an increase in the fatigue limit. After aging treatment, the higher strength of the Inconel 718 alloy made dislocation slip difficult under high cycle fatigue loads, and the plasticity compatible deformation capability was poor. When local dislocations slipped to the intragranular γ" phase, γ' phase, or interfaces with nonmetallic compounds (NMCs), plugging occurred. The degree of stress concentration increased, causing the initiation of fatigue fracture; the secondary fracture was approximately 20 µm. Brittle cleavage due to multiple sources significantly reduced the fatigue limit.

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“…Singh et al [20] has attributed this dual slope behaviour to a change in deformation mode from single slip at low strain amplitudes to multiple slip at higher strain amplitudes. However, Bhattacharya et al [21] have reported dual slope behaviour in IN718 superalloy at room temperature and it was attributed to a change in deformation mechanism from twinning at low strain amplitudes to slip band formation at high strain amplitudes. In wrought alloy Udimet 720 LI, Gopinath et al [22] have reported differences in the density of slip bands to be the cause of dual-slope behaviour while the slip character remained planar in nature from low to high strain amplitudes.…”

Section: Low Cycle Fatigue Propertiesmentioning

confidence: 99%

High temperature low cycle fatigue behaviour of hot isostatically pressed superalloy Udimet 720 LI

Prasad

Sarkar

Ghosal

et al. 2010

Materials at High Temperatures

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Nickel base superalloy Udimet 720 LI was processed through a powder metallurgy (PyM) hot isostatic pressing (HIP) route. The effects of this consolidation technique (HIPing) on low cycle fatigue (LCF) properties were evaluated and are reported in this paper. Total strain controlled LCF tests have been conducted in air at 550 C at a nominal strain rate of 6.67610 À 3 s À 1 . The as-HIPed Udimet 720 Li exhibits stable behaviour followed by very mild cyclic hardening at total strain amplitudes + 0.4 -0.5%. However, cyclic hardening has been observed at total strain amplitudes + 0.6 -1.2%. The cyclic hardening is attributed to dynamic strain aging (DSA). The dual slope behaviour in a Coffin-Manson plot is attributed to a change in fracture mechanism.

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On the dual slope coffin-manson relationship during low cycle fatigue of Ni-base alloy in 718

Cited by 16 publications

References 12 publications

Micromechanism of cyclic plastic deformation of alloy IN 718 at 600 °C

Micromechanism of cyclic plastic deformation of alloy IN 718 at 600 °C

High Cycle Fatigue Performance of Inconel 718 Alloys with Different Strengths at Room Temperature

High temperature low cycle fatigue behaviour of hot isostatically pressed superalloy Udimet 720 LI

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