Behaviour of short and long cracks in air and in liquid metal in T91 steel

The low cycle fatigue behaviour of a 9Cr1MoNbV martensitic steel has been investigated at 350°C in air and in lead-bismuth eutectic (LBE). Total strain controlled tests were performed from Δεt = 0.40% to 1.2%. The material exhibited a pronounced cyclic softening in both environments. LBE reduced the fatigue resistance. LBE accelerated the formation of the long crack by promoting the growth of the first short cracks. A clear change in propagation mode was observed. In air, ductile fatigue striations were observed while in LBE a brittle fracture decorated by voluminous and largely spaced striations were visible. From EBSD analysis, it was concluded that in LBE, the long crack advanced quickly by repeated and discontinuous cleavage.

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Multiscale investigation of quasi-brittle fracture characteristics in a 9Cr–1Mo ferritic–martensitic steel embrittled by liquid lead–bismuth under low cycle fatigue

Corrosion Science ◽

10.1016/j.corsci.2015.10.003 ◽

2016 ◽

Vol 102 ◽

pp. 137-152 ◽

Cited By ~ 21

Author(s):

Xing Gong ◽

Pierre Marmy ◽

Alexander Volodin ◽

Behnam Amin-Ahmadi ◽

Ling Qin ◽

...

Keyword(s):

Brittle Fracture ◽

Martensitic Steel ◽

Low Cycle Fatigue ◽

Liquid Lead ◽

Cycle Fatigue ◽

Fracture Characteristics

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Low cycle fatigue behaviour of T91 martensitic steel at 300°Cin air and in liquid lead bismuth eutectic

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2005.11.003 ◽

2006 ◽

Vol 28 (8) ◽

pp. 843-851 ◽

Cited By ~ 32

Author(s):

A VERLEENE ◽

J VOGT ◽

I SERRE ◽

A LEGRIS

Keyword(s):

Martensitic Steel ◽

Low Cycle Fatigue ◽

Fatigue Behaviour ◽

Liquid Lead ◽

Cycle Fatigue ◽

Lead Bismuth Eutectic

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Low Cycle Fatigue Behaviour of ODS Steels for Nuclear Application

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.465.556 ◽

2011 ◽

Vol 465 ◽

pp. 556-559 ◽

Cited By ~ 6

Author(s):

Ivo Kuběna ◽

Tomáš Kruml ◽

Benjamin Fournier ◽

Jaroslav Polák

Keyword(s):

Ferritic Steel ◽

Low Cycle Fatigue ◽

Cyclic Hardening ◽

Fatigue Behaviour ◽

Cyclic Softening ◽

Oxide Dispersion ◽

Cycle Fatigue ◽

Oxide Particles ◽

Ods Steels

This study deals with the low cycle fatigue (LCF) behaviour of two steels strengthened by oxide dispersion. The ODS Eurofer steel shows cyclic softening, slower than in the case of the same steel without oxide particles. The 14Cr ODS ferritic steel is cyclically stable, even a slight cyclic hardening is observed at 650 °C. The reasons for this different behaviour lie probably in the less resistant matrix with a lot of weak subgrain boundaries in ODS Eurofer, because no clear difference in the oxide particles distribution was found.

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Low Cycle Fatigue Behaviour of Al-Mg-Si Alloy AA6061 Processed by Equal Channel Angular Pressing

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.463-464.97 ◽

2012 ◽

Vol 463-464 ◽

pp. 97-101

Author(s):

C.V. Venkatesh ◽

S. Ganesh Sundara Raman ◽

Chakkingal Uday

Keyword(s):

Equal Channel Angular Pressing ◽

Room Temperature ◽

Low Cycle Fatigue ◽

Cyclic Hardening ◽

Fatigue Behaviour ◽

Cyclic Softening ◽

Cycle Fatigue ◽

Angular Pressing ◽

Processed Material ◽

Number Of Passes

The low cycle fatigue (LCF) behaviour of aluminium-magnesium-silicon alloy AA6061 processed by equal channel angular pressing (ECAP) was studied. Solutionized specimens of the alloy were subjected to one, two and three passes of ECAP at room temperature using route Bc. Compared to the values of the solutionized material an overall increase in yield strength and ultimate tensile strength with decrease in % elongation is observed for the ECAP processed material. While the solutionized material exhibits cyclic hardening at all strain levels, the ECAP processed material shows different behaviour depending on the number of passes - stable response/cyclic softening/ softening followed by hardening. The ECAP processed material after three passes exhibit superior LCF lives at low strains presumably due to higher strength and large refinement of grains.

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Effect of microstructural evolution on the cyclic softening of a 10% Cr martensitic steel under low cycle fatigue at 600 °C

International Journal of Fatigue ◽

10.1016/j.ijfatigue.2020.105522 ◽

2020 ◽

Vol 134 ◽

pp. 105522 ◽

Cited By ~ 1

Author(s):

R. Mishnev ◽

N. Dudova ◽

R. Kaibyshev

Keyword(s):

Microstructural Evolution ◽

Martensitic Steel ◽

Low Cycle Fatigue ◽

Cyclic Softening ◽

Cycle Fatigue

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Low cycle fatigue behavior and cyclic softening of P92 ferritic-martensitic steel

Journal of Iron and Steel Research International ◽

10.1016/s1006-706x(15)30037-6 ◽

2015 ◽

Vol 22 (6) ◽

pp. 534-542 ◽

Cited By ~ 17

Author(s):

Zhen Zhang ◽

Zheng-fei Hu ◽

Li-kun Fan ◽

Bin Wang

Keyword(s):

Martensitic Steel ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Cyclic Softening ◽

Cycle Fatigue

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A Unified Viscoplastic Model for High Temperature Low Cycle Fatigue of Service-Aged P91 Steel

Volume 6B: Materials and Fabrication ◽

10.1115/pvp2013-98003 ◽

2013 ◽

Author(s):

R. A. Barrett ◽

P. E. O’Donoghue ◽

S. B. Leen

Keyword(s):

High Temperature ◽

Low Cycle Fatigue ◽

Kinematic Hardening ◽

Material Model ◽

Fatigue Behaviour ◽

Cyclic Softening ◽

Flow Rule ◽

Strain Rates ◽

Cycle Fatigue ◽

Hyperbolic Sine

The finite element (FE) implementation of a hyperbolic sine unified cyclic viscoplasticity model is presented. The hyperbolic sine flow rule facilitates the identification of strain-rate independent material parameters for high temperature applications. This is important for the thermo-mechanical fatigue of power plant where a significant stress range is experienced during operational cycles and at stress concentration features, such as welds and branch connections. The material model is successfully applied to the characterisation of the high temperature low cycle fatigue behaviour of a service-aged P91 material, including isotropic (cyclic) softening and non-linear kinematic hardening effects, across a range of temperatures and strain-rates.

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Low-Cycle Fatigue Behaviour of Gas Turbine Alloys

Proceedings of the Institution of Mechanical Engineers ◽

10.1243/pime_proc_1974_188_037_02 ◽

1974 ◽

Vol 188 (1) ◽

pp. 321-328 ◽

Cited By ~ 1

Author(s):

W. J. Evans ◽

G. P. Tilly

Keyword(s):

Low Cycle Fatigue ◽

Fatigue Cracks ◽

High Stress ◽

Cyclic Creep ◽

Fatigue Curve ◽

Fatigue Behaviour ◽

Material Surface ◽

Tension Stress ◽

Cycle Fatigue ◽

Stress Tests

The low-cycle fatigue characteristics of an 11 per cent chromium steel, two nickel alloys and two titanium alloys have been studied in the range 20° to 500°C. For repeated-tension stress tests on all the materials, there was a sharp break in the stress-endurance curve between 103 and 104 cycles. The high stress failures were attributed to cyclic creep contributing to the development of internal cavities. At lower stresses, failures occurred through the growth of fatigue cracks initiated at the material surface. The whole fatigue curve could be represented by an expression developed from linear damage assumptions. Data for different temperatures and types of stress concentration were correlated by expressing stress as a fraction of the static strength. Repeated-tensile strain cycling data were represented on a stress-endurance diagram and it was shown that they correlated with push-pull stress cycles at high stresses and repeated-tension at low stresses. In general, the compressive phase tended to accentuate cyclic creep so that ductile failures occurred at proportionally lower stresses. Changes in frequency from 1 to 100 cycle/min were shown to have no significant effect on low-cycle fatigue behaviour.

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