Ultra Low Cycle Fatigue of Axisymmetric Freestanding Nanoscale Gold Films

We present ultra low-cycle fatigue experiments of axisymmetric nano-crystalline gold films of nano-thickness deformed by a spherical indenter using a recently developed freestanding membrane test. Freestanding membranes of gold were centrally deflected using a spherical indenter attached to a MEMS load cell. Fabrication of the films for these experiments yielded films 100 nm thick and 500 μm in diameter. We observed that the plastically deformed thin films recover completely in time at room temperature. One particular film was loaded 4 consecutive times, with the fourth loading leading to its fracture after full recovery from the three prior loadings. Observation of this phenomenon directed us to term this behavior “Ultra Low cycle fatigue”.

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Estimation of low-cycle fatigue damage of sputtered Cu thin films at the micro scale using deep learning

Mechatronics ◽

10.1016/j.mechatronics.2021.102606 ◽

2021 ◽

Vol 78 ◽

pp. 102606

Author(s):

Michiaki Kamiyama ◽

Kazuteru Shimizu ◽

Yoshiaki Akiniwa

Keyword(s):

Thin Films ◽

Deep Learning ◽

Fatigue Damage ◽

Low Cycle Fatigue ◽

Cycle Fatigue ◽

Micro Scale

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Impact of Temperature on Low-Cycle Fatigue Characteristics of the HR6W Alloy

Materials ◽

10.3390/ma14226741 ◽

2021 ◽

Vol 14 (22) ◽

pp. 6741

Author(s):

Grzegorz Junak ◽

Anżelina Marek ◽

Michał Paduchowicz

Keyword(s):

Fatigue Life ◽

Room Temperature ◽

Low Cycle Fatigue ◽

Fatigue Tests ◽

Total Strain ◽

Cycle Fatigue ◽

Fatigue Characteristics

This paper presents the results of tests conducted on the HR6W (23Cr-45Ni-6W-Nb-Ti-B) alloy under low-cycle fatigue at room temperature and at 650 °C. Fatigue tests were carried out at constant values of the total strain ranges. The alloy under low-cycle fatigue showed cyclic strengthening both at room temperature and at 650 °C. The degree of HR6W strengthening described by coefficient n’ was higher at higher temperatures. At the same time, its fatigue life Nf at room temperature was, depending on the range of total strain adopted in the tests, several times higher than observed at 650 °C.

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Short Crack Initiation during Low-Cycle Fatigue in SAF 2507 Duplex Stainless Steel

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.345-346.343 ◽

2007 ◽

Vol 345-346 ◽

pp. 343-346 ◽

Cited By ~ 5

Author(s):

M.C. Marinelli ◽

Suzanne Degallaix ◽

I. Alvarez-Armas

Keyword(s):

Stainless Steel ◽

Duplex Stainless Steel ◽

Room Temperature ◽

Low Cycle Fatigue ◽

Fatigue Cracks ◽

Surface Strain ◽

The Other ◽

Cycle Fatigue ◽

Cyclic Tests ◽

Characteristic Microstructure

In this work, the formation of fatigue cracks is considered as a nucleation process due to the development of a characteristic microstructure formed just beneath the specimen surface. Strain controlled cyclic tests were carried out at room temperature at total strain ranges εt = 0.8 and 1.2% in flat specimens of SAF 2507 Duplex Stainless Steel (DSS). The results show that for this DSS, at εt = 0.8%, the correlation between phases (Kurdjumov-Sacks crystallographic relation) plays an important role in the formation of microcracks. On the other hand, at εt = 1.2%, microcracks initiate in the ferritic phase and the K-S relation does not seem to affect the formation of the cracks.

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Low cycle fatigue of aluminium thin films on vibrating silicon MEMS cantilevers: Highly accelerated stress test and finite element modelling

2018 19th International Conference on Thermal, Mechanical and Multi-Physics Simulation and Experiments in Microelectronics and Microsystems (EuroSimE) ◽

10.1109/eurosime.2018.8369941 ◽

2018 ◽

Author(s):

Georg M. Reuther ◽

Reinhard Pufall ◽

Bernhard Wunderle

Keyword(s):

Thin Films ◽

Finite Element ◽

Finite Element Modelling ◽

Low Cycle Fatigue ◽

Stress Test ◽

Cycle Fatigue ◽

Element Modelling ◽

Accelerated Stress Test ◽

Mems Cantilevers

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Relaxation in Nanoscale Freestanding Gold Films Using MEMS

Materials ◽

10.1115/imece2005-82833 ◽

2005 ◽

Author(s):

B. S. Samuel ◽

A. V. Desai ◽

M. A. Haque

Keyword(s):

Thin Films ◽

Stress Relaxation ◽

Room Temperature ◽

Gold Films ◽

Test Bed ◽

Scanning Microscope ◽

Substrate Effects ◽

Stress Relaxation Behavior ◽

Loading Device ◽

Film Specimen

We present experimental results to describe the stress relaxation behavior of thin (125 nm) freestanding gold films at room temperature. The experiments were performed inside a field emission scanning microscope using a MEMS-based test bed which is only 3mm × 10mm in size. The effect of stress relaxation on the young’s modulus of gold thin films is observed. The thin film specimen used in the experiment is co-fabricated with the micromechanical loading device and hence eliminates problems of alignment and gripping. Freestanding thin films provide us with information about the mechanical behavior of thin films in the absence of substrate effects.

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Low Cycle Fatigue of Nuclear Pipe Components

Journal of Pressure Vessel Technology ◽

10.1115/1.3454163 ◽

1974 ◽

Vol 96 (3) ◽

pp. 171-176 ◽

Cited By ~ 5

Author(s):

J. D. Heald ◽

E. Kiss

Keyword(s):

Stainless Steel ◽

Fatigue Life ◽

Room Temperature ◽

Fatigue Testing ◽

Low Cycle Fatigue ◽

304 Stainless Steel ◽

Code Design ◽

Hydraulic Pressure ◽

Cycle Fatigue ◽

Cyclic Bending

This paper presents the results of low-cycle fatigue testing and analysis of 26 piping components and butt-welded sections. The test specimens were fabricated from Type-304 stainless steel and carbon steel, materials which are typically used in the primary piping of light water nuclear reactors. Components included 6-in. elbows, tees, and girth butt-welded straight sections. Fatigue testing consisted of subjecting the specimens to deflection-controlled cyclic bending with the objective of simulating system thermal expansion type loading. Tests were conducted at room temperature and 550 deg F, with specimens at room temperature subjected to 1050 psi constant internal hydraulic pressure in addition to cyclic bending. In two tests at room temperature, however, stainless steel elbows were subjected to combined simultaneous cyclic internal pressure and cyclic bending. Predictions of the fatigue life of each of the specimens tested have been made according to the procedures specified in NB-3650 of Section III[1] in order to assess the code design margin. For the purpose of the assessment, predicted fatigue life is compared to actual fatigue life which is defined as the number of fatigue cycles producing complete through-wall crack growth (leakage). Results of this assessment show that the present code fatigue rules are adequately conservative.

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