The low Cycle Fatigue Behavior of Three advanced Nickel-Base Eutectic Composites

1981 ◽  
Vol 12 ◽  
Author(s):  
T. Ishii ◽  
D. J. Duquette ◽  
N. S. Stoloff
Keyword(s):  
Plastic Strain ◽  
Linear Relation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Metals And Alloys ◽  
Cycle Fatigue ◽  
Plastic Strain Range ◽  
Nickel Base

AbstractThe low cycle fatigue behavior at 25°C and 825°C of three advanced nickel-base eutectics is described. Fatigue lives are shown to obey a linear relation with plastic strain range (Coffin-Manson relation) but lives are much lower than are observed for conventional metals and alloys. Cyclic hardening and softening were observed in each alloy at 25 °C; however, this behavior differs from the classical saturation behavior observed with isotropic materials.

Low-Cycle Fatigue Life of Continuously Cyclic-Hardening Material

2020 ◽  
Author(s):  
Zhong Zhang ◽  
Xijia Wu
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Root Mean Square ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Mean Square ◽  
Cycle Fatigue ◽  
Fatigue Crack Nucleation ◽  
Hardening Material ◽  
Plastic Strain Range

Abstract A general fatigue life equation is derived by modifying the Tanaka-Mura-Wu dislocation pile-up model for variable strain-amplitude fatigue processes, where the fatigue crack nucleation life is expressed in terms of the root mean square of plastic strain range. Low-cycle fatigue tests were conducted on an austenitic stainless steel. at 400°C and 600°C, the material exhibits continuously cyclic-hardening behaviour. The root mean square of plastic strain ranges is evaluated from the experimental data for each test condition at strain rates ranging from 0.0002/s to 0.02/s. The variable-amplitude Tanaka-Mura-Wu model is found to be in good agreement with the LCF data, which effectively proves Miner’s rule on the stored plastic strain energy basis.

Low-Cycle Fatigue Life of Continuously Cyclic-Hardening Material

2021 ◽  
Author(s):  
Zhong Zhang ◽  
Xijia Wu
Keyword(s):  
Fatigue Life ◽  
Plastic Strain ◽  
Root Mean Square ◽  
Low Cycle Fatigue ◽  
Cyclic Hardening ◽  
Mean Square ◽  
Cycle Fatigue ◽  
Fatigue Crack Nucleation ◽  
Hardening Material ◽  
Plastic Strain Range

Abstract A general fatigue life equation is derived by modifying the Tanaka-Mura-Wu dislocation pile-up model for variable strain-amplitude fatigue processes, where the fatigue crack nucleation life is expressed in terms of the root mean square of plastic strain range. Low-cycle fatigue tests were conducted on an austenitic stainless steel. At 400 ? and 600 ?, the material exhibits continuously cyclic-hardening behaviour. The root mean square of plastic strain ranges is evaluated from the experimental data for each test condition at strain rates ranging from 0.0002/s to 0.02/s. The variable-amplitude Tanaka-Mura-Wu model is found to be in good agreement with the LCF data, which effectively proves Miner's rule on the stored plastic strain energy basis.

Low Cycle Fatigue Behavior of a New Type of Zircaloy Material

2011 ◽  
Vol 80-81 ◽  
pp. 788-791
Author(s):  
Wei Wei Yu ◽  
Fei Xue ◽  
Xin Ming Meng ◽  
Lei Lin
Keyword(s):  
Room Temperature ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cycle Fatigue ◽  
Fatigue Lifetime ◽  
Softening Behavior ◽  
New Type

To investigate the property of a new type of Zircaloy material, a low cycle fatigue (LCF) test has been performed at room temperature (RT) and 375°C. Results show that the new alloy generally displays cyclic hardening followed by a continuous softening behavior. Fatigue lifetime curves as a function of strain range imply that the new alloy has a nearly same lifetime than that of Zr-4 at RT, and superior than that at 375°C.

scholarly journals Thermal-Stress and Low-Cycle Fatigue Data on Typical Materials

1965 ◽  
Author(s):  
K. E. Horton ◽  
J. M. Hallander ◽  
D. D. Foley
Keyword(s):  
Plastic Strain ◽  
Low Cycle Fatigue ◽  
Mechanical Strain ◽  
Thermal Strain ◽  
Strain Range ◽  
Fatigue Tests ◽  
Cycle Fatigue ◽  
Ferrous Alloys ◽  
Plastic Strain Range ◽  
Analysis Of Results

This paper presents the results of low-cycle-fatigue tests wherein either thermal strain or mechanical strain was the independent variable. The materials investigated were primarily ferrous alloys for use in nuclear reactors. The analysis of results was based on plastic-strain-range measurements which could be made reproducibly in the 2 × 10−5 range. Graphs of plastic strain range versus cycles to failure were often found to be independent of large variations in temperature and cycle time. The results from thermal-fatigue and constant-temperature-fatigue tests were usually indistinguishable on these graphs, suggesting that identical metallurgical phenomena occurred in each type of test.

Low Cycle Fatigue of Alloy 617 at 850 °C and 950 °C

2013 ◽  
Vol 135 (3) ◽  
Author(s):  
J. K. Wright ◽  
L. J. Carroll ◽  
J. A. Simpson ◽  
R. N. Wright
Keyword(s):  
Strain Rate ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Solute Drag ◽  
Cycle Fatigue ◽  
Alloy 617 ◽  
Total Strain Range ◽  
Cycles To Failure

The low cycle fatigue behavior of Alloy 617 has been evaluated at 850 °C and 950 °C, the temperature range of particular interest for the intermediate heat exchanger on a proposed high-temperature gas-cooled nuclear reactor. Cycles to failure were measured as a function of total strain range and varying strain rate. Results of the current experiments compare well with previous work reported in the literature for a similar range of temperatures and strain rate. The combined data demonstrate a Coffin–Manson relationship, although the slope of the Coffin–Manson fit is close to −1 rather than the typically reported value of −0.5. At 850 °C and a strain rate of 10−3 /s Alloy 617 deforms by a plastic flow mechanism in low cycle fatigue and exhibits some cyclic hardening. At 950 °C for strain rates of 10−3–10−5 /s, Alloy 617 deforms by a solute drag creep mechanism during low cycle fatigue and does not show significant cyclic hardening or softening. At this temperature the strain rate has little influence on the cycles to failure for the strain ranges tested.

scholarly journals Limit, Shakedown and Ratchet Analyses of Defective Pipeline Under Internal Pressure and Cyclic Thermal Loading

2011 ◽  
Author(s):  
Weihang Chen ◽  
Haofeng Chen ◽  
Tianbai Li ◽  
James Ure
Keyword(s):  
Plastic Strain ◽  
Internal Pressure ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Collapse Mechanism ◽  
Cycle Fatigue ◽  
Matching Method ◽  
Plastic Strain Range ◽  
Fatigue Assessment ◽  
Linear Matching Method

In this study, the limit load, shakedown and ratchet limit of a defective pipeline subjected to constant internal pressure and a cyclic thermal gradient are analyzed. Ratchet limit and maximum plastic strain range are solved by employing the new Linear Matching Method (LMM) for the direct evaluation of the ratchet limit. Shakedown and ratchet limit interaction diagrams of the defective pipeline identifying the regions of shakedown, reverse plasticity, ratcheting and plastic collapse mechanism are presented and parametric studies involving different types and dimensions of part-through slot in the defective pipeline are investigated. The maximum plastic strain range over the steady cycle with different cyclic loading combinations is evaluated for a low cycle fatigue assessment. The location of the initiation of a fatigue crack for the defective pipeline with different slot type is determined. The proposed linear matching method provides a general-purpose technique for the evaluation of these key design limits and the plastic strain range for the low cycle fatigue assessment. The results for the defective pipeline shown in the paper confirm the applicability of this procedure to complex 3-D structures.

Definition of Damage Parameter in Low-Cycle Fatigue of Gray Cast Iron

2007 ◽  
Vol 345-346 ◽  
pp. 367-370 ◽  
Author(s):  
Keum Oh Lee ◽  
Soon Bok Lee
Keyword(s):  
Cast Iron ◽  
Plastic Strain ◽  
Gray Cast Iron ◽  
Low Cycle Fatigue ◽  
Strain Range ◽  
Damage Parameter ◽  
Gray Cast ◽  
Graphite Flake ◽  
Cycle Fatigue ◽  
Plastic Strain Range

Gray cast iron shows large asymmetrical features by the graphite flake when tensile and compressive stresses are applied. The plastic strain rage which is used in low-cycle fatigue life prediction by many researchers is hardly defined and gives very different values by the Standards in this case. From the results of this study, it is not reliable to use the plastic strain range as a low-cycle fatigue damage parameter. Therefore, the plastic strain energy density which is uniquely defined was suggested as a damage parameter and it showed good correlation in low-cycle fatigue in gray cast iron.

Isothermal Fatigue Behaviour of Two Nickelbase Alloys for Turbine Blades of Fighter Aircraft Engines

2013 ◽  
Author(s):  
Benudhar Sahoo ◽  
R. K. Satpathy ◽  
S. K. Panigrahi
Keyword(s):  
Plastic Strain ◽  
Cast Alloy ◽  
Fatigue Behavior ◽  
Turbine Blades ◽  
Strain Range ◽  
Cyclic Hardening ◽  
Cyclic Softening ◽  
Plastic Strain Amplitude ◽  
Isothermal Fatigue ◽  
Nickel Base

Turbine blades of fighter class aero-engines are subjected to repeated and unsteady throttle excursions during exploitation leading to thermo-mechanical fatigue. Failures of few turbine blades have led to premature withdrawals and major accidents. Hence, there is a need to study the high temperature fatigue behavior of these alloys. This case study deals with the isothermal fatigue behavior at 900°C for two nickel base alloys which are used for manufacturing turbine blades. The materials selected for study are precipitation strengthened wrought nickel base super alloy AP 220BD of Russian origin and western origin nickel base DS cast alloy MAR-M 002. Tensile and low cycle fatigue (LCF) tests were carried out at 900°C. LCF test was carried out at three strain ranges Δεt, i.e., ±0.3%, ±0.5% and ±0.8% using a triangular waveform of frequency 0.33 Hz with the help of MTS 800 servo hydraulic fatigue testing machine. Fractography and metallography have been done on the fracture surface to study the mode of failure and changes in morphology. Both AP220BD and MAR M 002 shows initial cyclic softening followed by cyclic hardening at low strain Δεt, i.e., ±0.3%. Stabilisation of hysteresis loop takes place at strain range Δεt ±0.5% for both the alloys. At Δεt/2 = 0.8%, AP220 BD shows cyclic hardening while MAR M 002 shows cyclic softening. MAR M 002 shows higher degree of hardening compared to that of AP220BD. The reduction in LCF life with increase in strain range is exponential for wrought alloy but for DS cast alloy it is approximately linear. LCF life has been correlated with fatigue damage parameters such as Ostergren energy(σmax Δεp) and plastic strain amplitude Δεp/2. Ostergren energy for MAR-M 002 is found to be significantly less compared to that of AP220BD. The increase in plastic strain range Δεp is significant for wrought alloys. While Ostergren energy is a good indicator of fatigue damage for wrought alloy, plastic strain amplitude Δεp/2 seems to be a better indicator for DS cast alloy. Fractography reveals inter-granular failure with initiation of cracks at at grain boundary / carbides in wrought alloy. DS cast alloy shows cleavage failure with crack initiation at pore cavities in interdendritic spacing.

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