scholarly journals Low Cycle Fatigue Performance of Additively Processed and Heat-Treated Ti-6Al-7Nb Alloy for Biomedical Applications

Metals ◽  
2022 ◽  
Vol 12 (1) ◽  
pp. 122
Author(s):  
Maxwell Hein ◽  
David Kokalj ◽  
Nelson Filipe Lopes Dias ◽  
Dominic Stangier ◽  
Hilke Oltmanns ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Tensile Tests ◽  
Cyclic Fatigue ◽  
Recrystallization Annealing ◽  
Cycle Fatigue ◽  
Microstructural Investigation ◽  
Heat Treated ◽  
Stress Relieving

In biomedical engineering, laser powder bed fusion is an advanced manufacturing technology, which enables, for example, the production of patient-customized implants with complex geometries. Ti-6Al-7Nb shows promising improvements, especially regarding biocompatibility, compared with other titanium alloys. The biocompatible features are investigated employing cytocompatibility and antibacterial examinations on Al2O3-blasted and untreated surfaces. The mechanical properties of additively manufactured Ti-6Al-7Nb are evaluated in as-built and heat-treated conditions. Recrystallization annealing (925 °C for 4 h), β annealing (1050 °C for 2 h), as well as stress relieving (600 °C for 4 h) are applied. For microstructural investigation, scanning and transmission electron microscopy are performed. The different microstructures and the mechanical properties are compared. Mechanical behavior is determined based on quasi-static tensile tests and strain-controlled low cycle fatigue tests with total strain amplitudes εA of 0.35%, 0.5%, and 0.8%. The as-built and stress-relieved conditions meet the mechanical demands for the tensile properties of the international standard ISO 5832-11. Based on the Coffin–Manson–Basquin relation, fatigue strength and ductility coefficients, as well as exponents, are determined to examine fatigue life for the different conditions. The stress-relieved condition exhibits, overall, the best properties regarding monotonic tensile and cyclic fatigue behavior.

Multiaxial Low Cycle Fatigue Life Prediction at 300 °C Using Equivalent Strain Appoach

2011 ◽  
Vol 361-363 ◽  
pp. 1669-1672
Author(s):  
Wen Xiao Zhang ◽  
Guo Dong Gao ◽  
Guang Yu Mu
Keyword(s):  
Fatigue Life ◽  
Life Prediction ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Strain Range ◽  
Cyclic Fatigue ◽  
Equivalent Strain ◽  
Multiaxial Fatigue ◽  
Fatigue Life Prediction ◽  
Cycle Fatigue

The low cycle fatigue behavior was experimentally studied with the 3-dimension notched LD8 aluminum alloy specimens at 300°C. The 3- dimension stress-strain responses of specimens were calculated by means of the program ADINA. The multiaxial fatigue life prediction was carried out according to von Mises’s equivalent theory. The results from the prediction showed that the equivalent strain range can be served as the valid mechanics for predicting multiaxial high temperature and low cyclic fatigue life.

Experimental Study of Viscoelastic Dampers under Large Deformation

2012 ◽  
Vol 166-169 ◽  
pp. 2226-2233 ◽  
Author(s):  
Gang Zhao ◽  
Peng Pan ◽  
Jia Ru Qian ◽  
Jin Song Lin
Keyword(s):  
Mechanical Properties ◽  
Experimental Study ◽  
Energy Dissipation ◽  
Low Cycle Fatigue ◽  
Loss Modulus ◽  
Fatigue Behavior ◽  
Fatigue Tests ◽  
Small Displacement ◽  
Loading Frequency ◽  
Cycle Fatigue

The paper presents an experimental study on a new type viscoelastic damper, which is expected to have better energy dissipation capability. Tests on the dampers’ mechanical properties, including shear storage modulus, shear loss modulus, and loss factor, were conducted using reduced scale specimens, and took strain amplitude, loading frequency and ambient temperature as test parameters. Aging tests, low cycle and high cycle fatigue tests were also conducted. Particularly, the low cycle fatigue behavior under a strain of 300% and the basic mechanical behavior under strains of 300%-420% were investigated. Test results suggest that the dependency of the mechanical properties on frequency and temperature is small, the energy dissipation capacity is stable for both large and small displacement, and the damper reaches a strain of 420% without failure.

The Effect of Alloy Elements on Cyclic Fatigue Behavior of Bucket Candidate Materials for USC Power Plants

2007 ◽  
Vol 26-28 ◽  
pp. 1141-1144 ◽  
Author(s):  
Kuk Cheol Kim ◽  
Byung Hoon Kim ◽  
Jin Ik Suk ◽  
Dong Soo Kim ◽  
Jeong Tae Kim
Keyword(s):  
Fatigue Life ◽  
Power Plants ◽  
Boron Content ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Cyclic Fatigue ◽  
Strengthening Effect ◽  
Cycle Fatigue ◽  
Commercial Steel ◽  
Power Plant Operation

The demand for ultra supercritical (USC) power plants has increased due to the need for high thermal efficiency and reduced CO2 emissions. For turbine materials, high-cycle and lowcycle fatigue life at USC service temperatures are needed to verify material integrity due to the heat-up and cool-down process of power plant operation and due to turbine variations during operation. In this paper, fatigue characteristics for 9~12 Cr steels as candidate USC bucket materials were investigated. First, the fatigue life between DS2B2 and COST B2 steel were compared. COST B2 is the commercial steel with improved high temperature properties by adding boron, and DS2B2 is the new steel developed by Doosan by adding Co and adjusting Mo and W based on the same Mo equivalent value (%wt. Mo + 1/2 %wt. W). DS2B2 steel was found to have longer low cycle fatigue life than COST B2. Second, the effect of boron on fatigue life for bucket materials based on COST B2 steel was investigated. At room temperature, as boron content increased, low cycle fatigue life became superior, whereas, at 593oC the fatigue life was similar. For high cycle fatigue, as boron content increased, fatigue life increased due to the strengthening effect by the addition of boron.

An experimental investigation on low-cycle fatigue behavior of GO-NH2-reinforced epoxy adhesive

2020 ◽  
pp. 146442072097754
Author(s):  
Jamal Dabbagh ◽  
Bashir Behjat ◽  
Mojtaba Yazdani ◽  
Lucas FM da Silva
Keyword(s):  
Mechanical Properties ◽  
Graphene Oxide ◽  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Epoxy Adhesive ◽  
Cycle Fatigue ◽  
Hummers Method ◽  
Optimum Weight ◽  
Modified Hummers Method

In this study, the effect of adding functionalized aminated graphene oxide up to 0.3 wt% was experimentally investigated on the mechanical properties and fatigue behavior of an epoxy adhesive with intermediate toughness. Accordingly, graphene oxide was prepared by a modified Hummers method and was modified with 3-aminopropyltrimethoxysilane silane agent. Bulk samples were then prepared from neat and reinforced adhesive with different weight amounts of aminated graphene oxide. Dumbbell-shaped samples with a notch were used to limit displacement at break. The results showed the presence of 0.1 wt% and 0.3 wt% aminated graphene oxide nanoplatelets, as optimum weight percentages respectively for the mechanical properties and the fatigue life, improves the modulus of elasticity by 35% and the tensile strength by 44% as well as the fatigue life by about 72–241% under different cyclic loading conditions.

Influence of Hold-Time and Temperature on the Low-Cycle Fatigue of Incoloy 800

1972 ◽  
Vol 94 (3) ◽  
pp. 930-934 ◽  
Author(s):  
C. E. Jaske ◽  
H. Mindlin ◽  
J. S. Perrin
Keyword(s):  
Fatigue Life ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Compressive Strain ◽  
Hold Time ◽  
Strain Range ◽  
Cyclic Fatigue ◽  
Cycle Fatigue ◽  
Incoloy 800 ◽  
Strain Cycling

A study has been conducted to determine the low-cycle fatigue behavior of solution-annealed Incoloy 800 bar at temperatures from 800–1400 deg F. The experimental work included evaluation of specimens under both continuous, completely reversed strain cycling and under strain cycling with hold time periods at the strain limits. At 1000, 1200, and 1400 deg F, it was found that 10-min hold-times at the tensile strain limit during every cycle significantly reduced the cyclic fatigue life compared to continuous cycling. However, there was little reduction in cyclic fatigue life when 10-min hold-times were introduced at the compressive strain limits or at both the tensile and compressive limits. The ratio of hold-time cyclic fatigue life to no-hold-time cyclic fatigue life decreased as the length of hold time increased (at constant total strain range) and as the magnitude of strain range decreased (at constant hold-time length).

Low Cycle Fatigue of Electrodeposited Pure Nanocrystalline Metals

2007 ◽  
Vol 561-565 ◽  
pp. 1299-1302 ◽  
Author(s):  
Pasquale Cavaliere
Keyword(s):  
Mechanical Properties ◽  
Grain Size ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Low Cycle Fatigue ◽  
Fatigue Behavior ◽  
Fatigue Crack Initiation ◽  
Size Variation ◽  
Load Ratio ◽  
Cycle Fatigue

The fatigue behavior of metals is strongly governed by the grain size variation. As the tensile strength, the fatigue limit increases with decreasing grain size in the microcrystalline regime. A different trend in mechanical properties has been demonstrated in many papers for metals with ultrafine (< 1 m) and nanocrystalline (< 100 nm) grain size in particular in the yield stress and fatigue crack initiation and growth. The fatigue behavior of electrodeposited nanocrystalline Ni (20 and 40 nm mean grain size) and nanocrystalline Co (20 nm) has been analyzed in the present paper by means of stress controlled tests. The monothonic mechanical properties of the materials were obtained from tensile tests by employing an Instron 5800 machine by measuring the strain with an extensometer up to 2.5% maximum strain. The strain gage specimen dimensions measured 20 mm length and 5 mm width, all the specimens were produced by electro-discharge machining. The low cycle fatigue tests were performed with specimens of the same geometry of the tensile ones in tension-tension with load ratio R=0.25. The fatigue crack propagation experiments were carried out by employing single edge notched specimens measuring 39 mm in length, 9.9 mm in width and with an electro-discharge machined edge-notch of 1 mm. All the endurance fatigue and crack propagation tests were performed at 10 Hz.

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