Temperature dependence of correlation between low cycle fatigue life and tensile strength in cast Ni and Co base superalloys at elevated temperatures.

This paper describes the notch effect in biaxial low cycle fatigue of an austenitic stainless steel SUS 304 at 873K in air. Mises’ equivalent stress controlled fatigue tests were carried out for the three kinds of round notched specimens in push-pull/torsion biaxial stress states. Cracks emanated at the notch root were measured by a d.c. potential drop method. Reduction in the fatigue life due to the notch was most significant in the reversed torsion test in comparison with the push-pull and combined push-pull/reversed torsion tests. The conventional fatigue life prediction methods, i.e., the Neuber’s rule, the Stowell’s method, and the Koe’s method, were applied to the experimental data and the accuracy of the prediction methods were discussed.

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Tensile and Fatigue Properties of Miniature Size Specimen of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge Lead-Free Solder

Materials Science Forum ◽

10.4028/www.scientific.net/msf.941.2081 ◽

2018 ◽

Vol 941 ◽

pp. 2081-2086

Author(s):

Masaki Yokoi ◽

Tatsuya Kobayashi ◽

Ikuo Shohji

Keyword(s):

Tensile Strength ◽

Fatigue Life ◽

Low Cycle Fatigue ◽

Ternary Eutectic ◽

Lead Free ◽

Fatigue Properties ◽

Lead Free Solder ◽

Cycle Fatigue ◽

Proof Stress ◽

Free Solder

Tensile and low cycle fatigue properties of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge (mass%) lead-free solder were investigated using miniature size specimens and obtained data were compared to those of Sn-3.0Ag-0.5Cu (mass%). The microstructure of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge consists of dendritic β-Sn phases and ternary eutectic phases surrounding them which are composed of β-Sn, (Cu,Ni)6Sn5 and Ag3Sn. Tensile strength and 0.1% proof stress of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge are superior to those of Sn-3.0Ag-0.5Cu at 25°C and 150°C. However, elongation of it is inferior to that of Sn-3.0Ag-0.5Cu at both temperatures. Fatigue lives of both alloys obey the Manson-Coffin equation and are analogous at 25°C. Although fatigue lives of both alloys decrease at 150°C, the fatigue life of Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge is inferior to that of Sn-3.0Ag-0.5Cu. At 150°C, the crack mainly progresses at grain boundaries of recrystallized grains. Sn-3.5Ag-0.5Cu-0.07Ni-0.01Ge has several grain boundaies which can be the origin of the crack so that fatigue lives degrade at 150°C.

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Low Cycle Fatigue Behavior of 429EM Ferritic Stainless Steel at Elevated Temperatures

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.261-263.1135 ◽

2004 ◽

Vol 261-263 ◽

pp. 1135-1140 ◽

Cited By ~ 5

Author(s):

Keum Oh Lee ◽

Sam Son Yoon ◽

Soon Bok Lee ◽

Bum Shin Kim

Keyword(s):

Stainless Steel ◽

Elastic Modulus ◽

Fatigue Life ◽

Elevated Temperatures ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Cyclic Hardening ◽

Dynamic Strain ◽

Temperature Structure ◽

Cycle Fatigue

In recent, ferritic stainless steels are widely used in high temperature structure because of their high resistance in thermal fatigue and low prices. Tensile and low cycle fatigue(LCF) tests on 429EM stainless steel were performed at several temperatures from room temperature to 600°C. Elastic modulus, yield stress and ultimate tensile strength(UTS) decreased with increasing temperature. Considerable cyclic hardening occurred at 200°C and 400°C. 475°C embrittlement observed could not explain this phenomenon but dynamic strain aging(DSA) observed from 200°C to 500°C could explain the hardening mechanism at 200°C and 400°C. And it was observed that plastic strain energy density(PSED) was useful to predict fatigue life when large cyclic hardening occurred. Fatigue life using PSED over elastic modulus could be well predicted within 2X scatter band at various temperatures.

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Prediction of low cycle fatigue life of short fibre composites at elevated temperatures using surrogate modelling

Composites Part B Engineering ◽

10.1016/j.compositesb.2011.04.047 ◽

2011 ◽

Vol 42 (6) ◽

pp. 1453-1460 ◽

Cited By ~ 12

Author(s):

Jung Hoon Sul ◽

B. Gangadhara Prusty ◽

Tapabrata Ray

Keyword(s):

Fatigue Life ◽

Elevated Temperatures ◽

Low Cycle Fatigue ◽

Short Fibre ◽

Cycle Fatigue ◽

Surrogate Modelling ◽

Fibre Composites

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Numerical and Analytical Analysis of the Low Cycle Fatigue Behavior of Notched and Un-Notched 316 L (N) Austenitic Stainless-Steel Samples at Ambient and Elevated Temperatures

Materials Proceedings ◽

10.3390/iec2m-09329 ◽

2021 ◽

Vol 3 (1) ◽

pp. 25

Author(s):

Ikram Abarkan ◽

Abdellatif Khamlichi ◽

Rabee Shamass

Keyword(s):

Stainless Steel ◽

Fatigue Life ◽

Elevated Temperatures ◽

Low Cycle Fatigue ◽

Fatigue Behavior ◽

Cycle Fatigue ◽

Corrosion Properties ◽

Notched Specimens ◽

Different Temperatures ◽

New Equation

Smooth and notched mechanical components made of metals frequently experience repeated cyclic loads at different temperatures. Thus, low cycle fatigue (LCF) is considered the dominant failure mode for these components. Stainless steel (SS) is the most widely selected material by engineers owing to its outstanding mechanical and LCF and anti-corrosion properties. Moreover, a reliable estimation of the fatigue life is essential in order to preserve people’s safety in industries. In the present study, an evaluation of some of the commonly known low cycle fatigue life methodologies are performed for notched and un-notched samples made of 316L (N) SS at ambient and higher temperatures. For the notched samples, the elastic–plastic strains were firstly determined and then the fatigue lives were estimated for constant nominal strain amplitudes, varying from ±0.4% to ±0.8%. A comparison between the calculated fatigue lives and those obtained experimentally from the literature was made. Overall, some of the widely used fatigue life prediction methods for smooth specimens have resulted in unsafe estimations for applied strain amplitudes ranging from ±0.3% to ±1.0%, and those of the notched specimens were generally found to give strongly conservative predictions. To overcome this problem, attempts were made to suggest new parameters that can precisely assess the lifetimes of smooth samples, and a new equation was suggested for notched samples under both room and high temperatures.

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ESTIMATION OF AXIAL FRETTING FATIGUE LIFE AT ELEVATED TEMPERATURES USING CRITICAL DISTANCE THEORY

Surface Review and Letters ◽

10.1142/s0218625x18500671 ◽

2018 ◽

Vol 25 (03) ◽

pp. 1850067 ◽

Cited By ~ 1

Author(s):

G. H. MAJZOOBI ◽

P. AZHDARZADEH

Keyword(s):

Fatigue Life ◽

Elevated Temperatures ◽

Low Cycle Fatigue ◽

Fretting Fatigue ◽

Critical Distance ◽

Fatigue Tests ◽

Elastic Behavior ◽

Cycle Fatigue ◽

Al 7075 ◽

Special Approach

Fretting fatigue life is traditionally estimated by experiment. The objective of this work is to introduce a special approach for estimation of axial fretting fatigue life at elevated temperatures from plain fatigue test based on the critical distance theory. The method uses Fatemi–Socie parameter as a multiaxial criterion to compute the stress multiaxiality on focus path. This method considers only elastic behavior for materials, and two characteristic diagrams are obtained from plain fatigue tests on two U-shaped and V-shaped notched specimens. The results showed reasonable agreement between the predictions by the proposed method and the experiments for ambient temperature. For elevated temperatures, the results indicated that the predicted fretting fatigue life was considerably overestimated in the low cycle fatigue (LCF) regime and underestimated in the high cycle fatigue (HCF) region with respect to experimental measurements. The reason for such discrepancy is believed to be due to the complex behavior of AL 7075-T6, which exhibits at elevated temperatures because of the problems such as aging, oxidation and reduction of strength.

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