scholarly journals High-Temperature Low-Cycle Fatigue Behaviour of MAR-M247 Coated with Newly Developed Thermal and Environmental Barrier Coating

2018 ◽  
Vol 2018 ◽  
pp. 1-8
Author(s):  
Ivo Šulák ◽  
Karel Obrtlík ◽  
Ladislav Čelko ◽  
Pavel Gejdoš ◽  
David Jech
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Constant Strain Rate ◽  
Total Strain Amplitude ◽  
Average Thickness ◽  
Cycle Fatigue ◽  
Air Plasma ◽  
Environmental Barrier ◽  
Environmental Barrier Coating ◽  
Barrier Coating

This study investigates the strain-controlled low-cycle fatigue (LCF) behaviour of an untreated and surface-treated MAR-M247 superalloy in a symmetrical push-pull cycle with a constant strain rate at 900°C in laboratory air. A newly developed experimental thermal and environmental barrier coating (TEBC) system, consisting of a 170 μm thick CoNiCrAlY bond coat (BC) and a bilayer ceramic top coat (TC), with an interlayer and an upper layer, was deposited using air plasma spray techniques. The ceramic interlayer with an average thickness of 77 μm was formed from agglomerated and sintered yttria-stabilized zirconia. An experimental mixture of mullite (Al6Si2O13) and hexacelsian (BaAl2Si2O8) at a ratio of 70/30 vol.% was sprayed as the upper layer. The average thickness of the TC was 244 μm. The specimen sections were investigated using a TESCAN Lyra3 XMU scanning electron microscope (SEM) to characterise the microstructure of both the TEBC and the substrate material. The fatigue damage mechanisms in the TEBC-coated superalloy were studied. The fatigue life curves in the representation of the total strain amplitude versus the number of cycles to failure of the TEBC-coated and uncoated superalloy were assessed. TEBC was found to have a slight, positive effect on the fatigue life of MAR-M247.

scholarly journals Low-cycle fatigue behaviour of laser welded high-strength steel DOMEX 700 MC

2018 ◽  
Vol 157 ◽  
pp. 05013 ◽  
Author(s):  
Peter Kopas ◽  
Milan Sága ◽  
František Nový ◽  
Bohuš Leitner
Keyword(s):  
Fatigue Life ◽  
Welded Joints ◽  
High Strength Steel ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Fatigue Behaviour ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Fatigue Life Analysis

The article presents the results of research on low cycle fatigue strength of laser welded joints vs. non-welded material of high-strength steel DOMEX 700 MC. The tests were performed under load controlled using the total strain amplitude ɛac. The operating principle of the special electro-mechanic fatigue testing equipment with a suitable clamping system was working on 35 Hz frequency. Fatigue life analysis was conducted based on the Manson-Coffin-Basquin equation, which made it possible to determine fatigue parameters. Studies have shown differences in the fatigue life of original specimens and laser welded joints analysed, where laser welded joints showed lower fatigue resistance. In this article a numerical analysis of stresses generated in bending fatigue specimens has been performed employing the commercially available FEM-program ADINA.

scholarly journals High-Strength Reinforcing Steel Bars: Low Cycle Fatigue Behavior Using RGB Methodology

2021 ◽  
Vol 15 (1) ◽  
Author(s):  
Jorge E. Egger ◽  
Fabian R. Rojas ◽  
Leonardo M. Massone
Keyword(s):  
Fatigue Life ◽  
Strain Amplitude ◽  
Low Cycle Fatigue ◽  
High Strength ◽  
Image Correlation ◽  
Total Strain ◽  
Total Strain Amplitude ◽  
Reinforcing Steel ◽  
Cycle Fatigue ◽  
Steel Bars

AbstractLow cycle fatigue life of high-strength reinforcing steel bars (ASTM A706 Grade 80), using photogrammetry by RGB methodology is evaluated. Fatigue tests are performed on specimens under constant axial displacement with total strain amplitudes ranging from 0.01 to 0.05. The experimental observations indicate that buckling of high-strength reinforcing bars results in a damaging degradation of their fatigue life performance as the slenderness ratio increases, including an early rebar failure as the total strain amplitude increases since it achieves the plastic range faster. In addition to this, the results show that the ratio of the ultimate tensile strength to yield strength satisfies the minimum of 1.25 specified in ASTM A706 for reinforcement. On the other hand, the RGB methodology indicates that the axial strains measured by photogrammetry provide more accurate data since the registered results by the traditional experimental setup do not detect second-order effects, such as slippage or lengthening of the specimens within the clamps. Moreover, the RGB filter is faster than digital image correlation (DIC) because the RGB methodology requires a fewer computational cost than DIC algorithms. The RGB methodology allows to reduce the total strain amplitude up to 45% compared to the results obtained by the traditional setup. Finally, models relating total strain amplitude with half-cycles to failure and total strain amplitude with total energy dissipated for multiple slenderness ratios (L/d of 5, 10, and 15) are obtained.

Microstructural Effects on Low Cycle Fatigue of Sn-3.8Ag-0.7Cu Pb-Free Solder

2007 ◽  
Vol 345-346 ◽  
pp. 239-242
Author(s):  
Qiu Lian Zeng ◽  
Zhong Guang Wang ◽  
J.K. Shang
Keyword(s):  
Fatigue Life ◽  
Cyclic Deformation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fracture Mechanisms ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Equiaxed Microstructure ◽  
Cyclic Frequency ◽  
Microstructural Effects

Low cycle fatigue behavior of Sn-3.8Ag-0.7Cu solder was investigated under fully reversed cyclic loading, with particular emphasis on microstructural effects. The LCF behavior of the solder with equiaxed microstructure was found to differ greatly from that of the solder with a dendrite microstructure. At a given total strain amplitude, the dendrite microstructure exhibited a much longer fatigue life than the equiaxed microstructure. Such a strong microstructural effect on fatigue life arose from the difference in cyclic deformation and fracture mechanisms between the two microstructures. A large number of microcracks along grain boundaries of the equiaxed structure solder developed with increasing cycling, while for the dendrite structure solder, cyclic deformation took place along the direction of the maximal shear stress during fatigue tests and microcracks initiated and propagated along shear deformation bands. Besides, the fatigue behavior of the dendritic microstructure was very sensitive to cyclic frequency whereas the fatigue behavior of the equiaxed microstructure showed less sensitivity to cyclic frequency.

Shear Strength of a Thermal Barrier Coating Parallel to the Bond Coat

1998 ◽  
Vol 120 (1) ◽  
pp. 26-32 ◽  
Author(s):  
T. A. Cruse ◽  
R. C. Dommarco ◽  
P. C. Basti´as
Keyword(s):  
Shear Strength ◽  
Thermal Barrier Coating ◽  
Bond Coat ◽  
Low Cycle Fatigue ◽  
High Stress ◽  
Test Method ◽  
Thermal Barrier ◽  
Cycle Fatigue ◽  
Air Plasma ◽  
Barrier Coating

The static and low cycle fatigue strength of an air plasma sprayed (APS) partially stabilized zirconia thermal barrier coating (TBC) is experimentally evaluated. The shear testing utilized the Iosipescu shear test arrangement. Testing was performed parallel to the TBC-substrate interface. The TBC testing required an innovative use of steel extensions with the TBC bonded between the steel extensions to form the standard losipescu specimen shape. The test method appears to have been successful. Fracture of the TBC was initiated in shear, although unconstrained specimen fractures propagated at the TBC-bond coat interface. The use of side grooves on the TBC was successful in keeping the failure in the gage section and did not appear to affect the shear strength values that were measured. Low cycle fatigue failures were obtained at high stress levels approaching the ultimate strength of the TBC. The static and fatigue strengths do not appear to be markedly different from tensile properties for comparable TBC material.

High Temperature Low Cycle Fatigue Characteristics of Grit Blasted Polycrystalline Ni-Base Superalloy

2015 ◽  
Vol 665 ◽  
pp. 73-76 ◽  
Author(s):  
Ivo Šulák ◽  
Karel Obrtlík ◽  
Ladislav Čelko
Keyword(s):  
Fatigue Life ◽  
Strain Amplitude ◽  
Low Cycle Fatigue ◽  
Total Strain ◽  
Material Surface ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Stress Strain ◽  
Fatigue Characteristics ◽  
Base Superalloy

The present work is focused on the study of low cycle fatigue behavior of grit blasted nickel-base superalloy Inconel 713LC (IN 713LC). Grit blasting parameters are obtained. Button end specimens of IN 713LC in as-received condition and with grit blasted surface were fatigued under strain control with constant total strain amplitude in symmetrical cycle at 900 °C in air. Hardening/softening curves, cyclic stress-strain curve and fatigue life data of both materials were obtained. Both materials exhibit the same stress-strain response. It has not been observed any improvement or reduction of low cycle fatigue life in representation of total strain amplitude versus number of cycles to failure of grit blasted material in comparison with as-received material. Surface relief and fracture surface were observed in SEM. The little effect of surface treatment on fatigue characteristics is discussed.

Influence of Heat Treatment Condition on Low Cycle Fatigue Life of a Rolled AZ80 Magnesium Alloy Sheet

2011 ◽  
Vol 239-242 ◽  
pp. 1309-1312
Author(s):  
Zhong Jun Wang
Keyword(s):  
Fatigue Life ◽  
Magnesium Alloy ◽  
Strain Amplitude ◽  
Low Cycle Fatigue ◽  
Solution Treatment ◽  
Alloy Sheet ◽  
Total Strain ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Az80 Magnesium Alloy

In this paper, the influence of ageing and solution treatment on the low cycle fatigue behavior of a rolled AZ80 magnesium alloy sheet was investigated at constant total strain amplitudes between 0.003 and 0.01. It was observed that fatigue life of the alloy sheet at as-rolled, ageing and solution treatment conditions can be described well by Coffin-Manson and Basquin’s equations. The fatigue parameters follow the two equations were evaluated. With increasing total strain amplitude, the fatigue life of the three conditions decreased. At the lowest total strain amplitude of 0.003, the fatigue life of the as-rolled alloy sheet was the biggest. However, at the highest total strain amplitude of 0.01, the fatigue life of solution treated alloy sheet was the biggest, and that of the ageing treated alloy sheet was the shortest.

Fatigue of an Advanced SiC/SiC Ceramic Matrix Composite With an Environmental Barrier Coating at Elevated Temperature in Air and in Steam

2020 ◽  
Author(s):  
T. M. Williams ◽  
M. B. Ruggles-Wrenn
Keyword(s):  
Ceramic Matrix Composite ◽  
Chemical Vapor ◽  
Chemical Vapor Infiltration ◽  
Air Plasma ◽  
Application Process ◽  
Environmental Barrier ◽  
Damage And Failure ◽  
Environmental Barrier Coating ◽  
Barrier Coating ◽  
Sic Ceramic

Abstract Uniaxial tension-tension fatigue performance of a SiC/SiC composite with an ytterbium-disilicate environmental barrier coating (EBC) was investigated at 1200°C in laboratory air and in steam. The composite is reinforced with Hi-Nicalon™ SiC fibers and has a melt-infiltrated matrix processed by chemical vapor infiltration of SiC followed by infiltration with SiC particulate slurry and molten Si. The EBC consists of a Si bond coat and an ytterbium disilicate (Yb2Si2O7) top coat applied via air plasma spraying (APS). Basic tensile properties of the EBC/SiC/SiC composite were evaluated at 1200°C. Tension-tension fatigue was examined for maximum stresses of 110–140 MPa in air and in steam. To assess the efficacy of the EBC, experimental results obtained for the coated composite are compared to those obtained for a control composite without the EBC. Surface grit-blasting inherent in the EBC application process degrades tensile strength of the composite. However, the EBC effectively protects the composite from oxidation embrittlement during cyclic loading in air or in steam. Fatigue runout defined as survival of 200,000 cycles (55.6 h at a frequency of 1.0 Hz) was achieved at 110 MPa in air and in steam. The retained properties of pre-fatigued specimens were characterized. Composite microstructure, as well as damage and failure mechanisms were investigated. Damage and failure of the EBC/SiC/SiC composite are attributed to growth of cracks originating from numerous processing defects (voids) present in the composite interior.

Effect of Gd and Y on the Low Cycle Fatigue Properties of AZ91D-0.4Ca-0.3Sr

2011 ◽  
Vol 197-198 ◽  
pp. 1536-1539
Author(s):  
Yong Chang Zhu ◽  
Shou Fan Rong ◽  
S. N. Shukayev ◽  
Jun Wang
Keyword(s):  
Fatigue Life ◽  
Magnesium Alloy ◽  
Strain Amplitude ◽  
Low Cycle Fatigue ◽  
Total Strain ◽  
Fatigue Properties ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Gravity Casting

The properties of gravity casting AZ91D-0.4Ca-0.3Sr alloy with Gd and Y in metal mould were studied by controlling the total strain amplitude ranged from 0.05mm to 0.25mm.under the conditions of the stress of ratio R equal to –1. In addition, the microstructure, phases, chemical constitute, fracture and low cycle fatigue behaviors of the magnesium alloy were primarily researched by means of SEM, EDAX and XRD and so on. The results showed that 3.0wt%Gd and 3.0wt%Y introduced the AZ91D-0.4Ca-0.3Sr alloy can refine α-Mg, and that Gd cooperating with Y can significantly improve the low cycle fatigue life. The low cycle fatigue times can be up to approximately 9874.

Effect of Thermal Barrier Coating on Low Cycle Fatigue Behavior of Cast Inconel 713LC at 900 °C

2014 ◽  
Vol 891-892 ◽  
pp. 848-853 ◽  
Author(s):  
Karel Obrtlík ◽  
Simona Hutařová ◽  
Ladislav Čelko ◽  
Martin Juliš ◽  
Tomáš Podrábský ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Thermal Barrier Coating ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Curve ◽  
Thermal Barrier ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Barrier Coating ◽  
Gauge Section

The effect of thermal barrier coating (TBC) on low cycle fatigue behavior of cast superalloy Inconel 713 LC has been studied at 900 °C. The TBC consisting of a CoNiCrAlY bond coat and a zirconia (ZrO2) top coat stabilized by 8% yttria (Y2O3) was deposited on the gauge section of cylindrical specimens using the atmospheric plasma spray technique. Cylindrical specimens of Inconel 713LC in as-received condition and with surface treatment were cyclically strained under strain control with constant total strain amplitude in symmetrical cycle at 900 °C in air. Hardening/softening curves, cyclic stress-strain curve and fatigue life data of coated and uncoated material were obtained. The stress response of the TBC coated specimens is lower in comparison with the uncoated specimens. Detrimental effect of surface treatment on the Basquin curve is documented. Specimen sectioning and fracture surface observations revealed fatigue damage mechanisms and help to discuss differences in fatigue behavior of the coated and uncoated superalloy.

Influence of the Strain Rate on the Low Cycle Fatigue Life of an Austenitic Stainless Steel with a Ground Surface Finish in Different Environments

2014 ◽  
Vol 891-892 ◽  
pp. 1320-1326 ◽  
Author(s):  
Thibault Poulain ◽  
José Mendez ◽  
Gilbert Hénaff ◽  
Laurent de Baglion
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Austenitic Stainless Steel ◽  
Strain Rate ◽  
Surface Finish ◽  
Power Plants ◽  
Low Cycle Fatigue ◽  
Total Strain Amplitude ◽  
Cycle Fatigue ◽  
Pressurized Water

This paper focuses on the influence of strain rate in Low Cycle Fatigue (LCF) of a 304L austenitic stainless steel at 300 °C in different environments (secondary vacuum, air and Pressurized Water Reactor (PWR) water environment). Moreover test samples are ground to obtain a surface finish rougher than all that could be found in nuclear power plants. Different strain rates (4x10-3, 1x10-4and 1x10-5s-1) are studied, with a triangular waveform at a total strain amplitude of ±0.6%. The influence of strain rate on cyclic stress-strain behavior and fatigue life is firstly analyzed in secondary vacuum, considered as a non-active environment. Then, interactions between stain rate and environmental effects in Air and in PWR environment are presented. In all environments, a decrease in strain rate leads to a negative strain rate dependence of the stress response and a reduction in fatigue life. Finally, SEM observations of fatigue striations in PWR environment indicate a crack propagation rate enhancement when the strain rate is decreased.

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