Effect of simultaneous B+ and N+2 implantation on microhardness, fatigue life, and microstructure in Fe–13Cr–15Ni base alloys

1989 ◽  
Vol 4 (6) ◽  
pp. 1371-1378 ◽  
Author(s):  
E. H. Lee ◽  
L. K. Mansur
Keyword(s):  
Fatigue Life ◽  
Fatigue Tests ◽  
Dislocation Slip ◽  
Transmission Electron ◽  
Austenitic Alloys ◽  
Life Improvement ◽  
Modified Surface ◽  
Nitrogen Ions ◽  
Alloying Compositions ◽  
Modified Surface Layer

Microhardness and cantilever beam fatigue measurements were conducted on Fe–13Cr–15Ni base austenitic alloys that were implanted with boron and nitrogen ions either singly or simultaneously. The microstructure of the modified surface layer and dislocation slip modes after fatigue tests were investigated by optical and transmission electron microscopy. Both hardness and fatigue life were improved by ion implantation, but the greatest improvement was achieved when boron and nitrogen were implanted simultaneously. The degree of fatigue life improvement also varied with minor changes in the base alloying compositions: nitrogen was detrimental or ineffective in the presence of titanium, and boron was much more effective in the presence of molybdenum. Comparison of slip band morphology between the compression and tension cycles indicated that implantation improved the reversibility of surface slip and delayed crack initiation.

The Effects of Mechanical Properties on Fatigue Behavior of ECAPed AA7075

2016 ◽  
Vol 35 (3) ◽  
pp. 225-234 ◽  
Author(s):  
Hasan Kaya ◽  
Mehmet Uçar
Keyword(s):  
Electron Microscope ◽  
Fatigue Life ◽  
Fatigue Behavior ◽  
Optical Microscope ◽  
Fatigue Tests ◽  
Angular Pressing ◽  
Four Point Bending ◽  
Selected Area Electron Diffraction ◽  
Transmission Electron ◽  
Hardness Values

AbstractIn this study, the effects of equal channel angular pressing (ECAP) on high-cycle fatigue and fatigue surface morphology of AA7075 have been investigated at a constant temperature (483 K) and the “C” route for four passes at ECAP process. ECAPed and as-received specimens were tested by four-point bending fatigue device. Fatigue tests were carried out by using 100, 120 and 140 MPa strength values. ECAPed specimens were characterized for each pass with optical microscope (OM), scanning electron microscope (SEM), energy-dispersive spectroscope (EDS), transmission electron microscope (TEM), selected area electron diffraction (SAED) and hardness measurements. Fracture surfaces of the specimens were also characterized with SEM. The results show that the highest hardness values (137 HV) and the best fatigue life (5.4 × 107for 100 MPa) were measured in ECAPed four-pass sample. For this reason hardness values and fatigue life were increased with increasing number of severe plastic deformation (SPD) process.

Zr+ Ion-Beam Surface Treatment of 30CrMnSiNi2 Steel for Improving its Fatigue Durability

2013 ◽  
Vol 872 ◽  
pp. 219-224 ◽  
Author(s):  
Ilya Vlasov ◽  
Sergey V. Panin ◽  
Viktor Sergeev ◽  
Vasilii Naidfeld ◽  
Mark Kalashnikov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Ion Beam ◽  
High Strength ◽  
X Ray Diffraction ◽  
Optical Scanning ◽  
Cyclic Tension ◽  
Transmission Electron ◽  
Beam Surface ◽  
Modified Surface ◽  
Modified Surface Layer

The structure of modified surface layer the high-strength 30CrMnSiNi2 steel was investigated by optical, scanning electron and transmission electron microscopy as well as X-ray diffraction methods. The tests on static and cyclic tension were performed for 30CrMnSiNi2 steel specimens in as supplied state and after nanostructuring surface layer by Zr+ ion beam. Differences of the specimen deformation behavior and changes of their mechanical properties are analyzed. The reason for fatigue life increase of the samples after the treatment is discussed.

Fatigue life improvement of threaded connections by cold rolling

2005 ◽  
Vol 40 (2) ◽  
pp. 83-93 ◽  
Author(s):  
M. J Knight ◽  
F. P Brennan ◽  
W. D Dover
Keyword(s):  
Fatigue Life ◽  
Cold Rolling ◽  
Rolling Process ◽  
Fatigue Tests ◽  
Stress Concentrations ◽  
Threaded Connections ◽  
Industry Standards ◽  
Operational Lifetime ◽  
Life Improvement ◽  
As Stress

Failures in drillstring threaded connections continue to afflict the oil industry at a cost of millions of dollars per year. In an attempt to reduce these failures the industry has generally adopted the fatigue-life-enhancing technique of cold rolling the threaded connections which act as stress concentrations. However, this beneficial process is only specified as optional in the industry standards, and where it is performed there is very little detail provided about this important process. This paper describes full-scale fatigue tests that investigate the cold-rolling process. From the development of cold-rolling equipment and the gathering of fatigue experimental data, several key factors have been identified that influence the operational lifetime of drillstring threaded connections.

scholarly journals Fatigue life improvement of cast ZK60 Mg alloy through low temperature closed-die forging for automotive applications

2018 ◽  
Vol 165 ◽  
pp. 06009 ◽  
Author(s):  
SMH. Karparvarfard ◽  
S.K. Shaha ◽  
S.B. Behravesh ◽  
H. Jahed ◽  
B. Williams
Keyword(s):  
Fatigue Life ◽  
Low Temperature ◽  
Yield Strength ◽  
Grain Refinement ◽  
Fatigue Tests ◽  
Cyclic Behaviour ◽  
Die Forging ◽  
Closed Die Forging ◽  
Texture Modification ◽  
Life Improvement

The influence of low-temperature closed-die forging on the quasi-static and cyclic behaviour of as-cast ZK60 magnesium alloy was investigated. As-cast ZK60 billets were forged at a ram speed of 20 mm/sec and a temperature of 250 °C. While the yield strength of the starting alloy was 139 MPa, the forging process improved the yield strength significantly by ~68% to 234 MPa. Moreover, the stresscontrolled push-pull fatigue tests at the stress amplitudes of 140 MPa to 180 MPa revealed that the fatigue life was enhanced by an order of magnitude. Microstructural analyses besides the texture measurements at different locations of the forged part manifested partial grain refinement and texture modification strengthening mechanisms. It is believed that the fatigue life improvement is achieved in the wake of the grain refinement and the subsequent material strengthening.

scholarly journals Experimental study on fatigue performance of Q420qD high-performance steel cross joint in complex environment

2021 ◽  
Author(s):  
Haigen Cheng ◽  
Cong Hu ◽  
Yong Jiang
Keyword(s):  
Fatigue Life ◽  
High Performance ◽  
Steel Structure ◽  
Steel Structures ◽  
Fatigue Tests ◽  
Fatigue Performance ◽  
Corrosive Media ◽  
Joint Connection ◽  
High Performance Steel ◽  
The Cross

AbstractThe steel structure under the action of alternating load for a long time is prone to fatigue failure and affects the safety of the engineering structure. For steel structures in complex environments such as corrosive media and fires, the remaining fatigue life is more difficult to predict theoretically. To this end, the article carried out fatigue tests on Q420qD high-performance steel cross joints under three different working conditions, established a 95% survival rate $$S{ - }N$$ S - N curves, and analyzed the effects of corrosive media and high fire temperatures on its fatigue performance. And refer to the current specifications to evaluate its fatigue performance. The results show that the fatigue performance of the cross joint connection is reduced under the influence of corrosive medium, and the fatigue performance of the cross joint connection is improved under the high temperature of fire. When the number of cycles is more than 200,000 times, the design curves of EN code, GBJ code, and GB code can better predict the fatigue life of cross joints without treatment, only corrosion treatment, and corrosion and fire treatment, and all have sufficient safety reserve.

scholarly journals Fatigue Testing of Wearable Sensing Technologies: Issues and Opportunities

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4070
Author(s):  
Andrea Karen Persons ◽  
John E. Ball ◽  
Charles Freeman ◽  
David M. Macias ◽  
Chartrisa LaShan Simpson ◽  
...  
Keyword(s):  
Fatigue Life ◽  
Prediction Models ◽  
Fatigue Testing ◽  
Low Cycle Fatigue ◽  
Wearable Sensors ◽  
Fatigue Tests ◽  
Proof Of Concept ◽  
Cycle Fatigue ◽  
Wearable Sensing ◽  
Failure Data

Standards for the fatigue testing of wearable sensing technologies are lacking. The majority of published fatigue tests for wearable sensors are performed on proof-of-concept stretch sensors fabricated from a variety of materials. Due to their flexibility and stretchability, polymers are often used in the fabrication of wearable sensors. Other materials, including textiles, carbon nanotubes, graphene, and conductive metals or inks, may be used in conjunction with polymers to fabricate wearable sensors. Depending on the combination of the materials used, the fatigue behaviors of wearable sensors can vary. Additionally, fatigue testing methodologies for the sensors also vary, with most tests focusing only on the low-cycle fatigue (LCF) regime, and few sensors are cycled until failure or runout are achieved. Fatigue life predictions of wearable sensors are also lacking. These issues make direct comparisons of wearable sensors difficult. To facilitate direct comparisons of wearable sensors and to move proof-of-concept sensors from “bench to bedside,” fatigue testing standards should be established. Further, both high-cycle fatigue (HCF) and failure data are needed to determine the appropriateness in the use, modification, development, and validation of fatigue life prediction models and to further the understanding of how cracks initiate and propagate in wearable sensing technologies.

scholarly journals Fatigue Life Improvement of Cracked Aluminum 6061-T6 Plates Repaired by Composite Patches

Materials ◽  
2021 ◽  
Vol 14 (6) ◽  
pp. 1421
Author(s):  
Armin Yousefi ◽  
Saman Jolaiy ◽  
Reza Hedayati ◽  
Ahmad Serjouei ◽  
Mahdi Bodaghi
Keyword(s):  
Fatigue Life ◽  
Fatigue Behavior ◽  
Weight Ratio ◽  
High Strength ◽  
Plastic Strain Amplitude ◽  
Composite Patch ◽  
Life Improvement ◽  
Cracked Structures ◽  
Aluminum Plates ◽  
High Flexibility

Bonded patches are widely used in several industry sectors for repairing damaged plates, cracks in metallic structures, and reinforcement of damaged structures. Composite patches have optimal properties such as high strength-to-weight ratio, easiness in being applied, and high flexibility. Due to recent rapid growth in the aerospace industry, analyses of adhesively bonded patches applicable to repairing cracked structures have become of great significance. In the present study, the fatigue behavior of the aluminum alloy, repaired by a double-sided glass/epoxy composite patch, is studied numerically. More specifically, the effect of applying a double-sided composite patch on the fatigue life improvement of a damaged aluminum 6061-T6 is analyzed. 3D finite element numerical modeling is performed to analyze the fatigue performance of both repaired and unrepaired aluminum plates using the Abaqus package. To determine the fatigue life of the aluminum 6061-T6 plate, first, the hysteresis loop is determined, and afterward, the plastic strain amplitude is calculated. Finally, by using the Coffin-Manson equation, fatigue life is predicted and validated against the available experimental data from the literature. Results reveal that composite patches increase the fatigue life of cracked structures significantly, ranging from 55% to 100% for different applied stresses.

An Investigation of Cyclic Transient Behavior and Implications on Fatigue Life Estimates

1997 ◽  
Vol 119 (2) ◽  
pp. 161-170 ◽  
Author(s):  
Yanyao Jiang ◽  
Peter Kurath
Keyword(s):  
Stainless Steel ◽  
Fatigue Life ◽  
Cyclic Hardening ◽  
Transient Behavior ◽  
Fatigue Tests ◽  
304 Stainless Steel ◽  
Deformation History ◽  
Life Estimation ◽  
Fatigue Life Estimation ◽  
Track Deformation

Current research focuses on proportional cyclic hardening and non-Massing behaviors. The interaction of these two hardenings can result in the traditionally observed overall softening, hardening or mixed behavior exhibited for fully reversed strain controlled fatigue tests. Proportional experiments were conducted with five materials, 304 stainless steel, normalized 1070 and 1045 steels, and 7075-T6 and 6061-T6 aluminum alloys. All the materials display similar trends, but the 304 stainless steel shows the most pronounced transient behavior and will be discussed in detail. Existing algorithms for this behavior are evaluated in light of the recent experiments, and refinements to the Armstrong-Frederick class of incremental plasticity models are proposed. Modifications implemented are more extensive than the traditional variation of yield stress, and a traditional strain based memory surface is utilized to track deformation history. Implications of the deformation characteristics with regard to fatigue life estimation, especially variable amplitude loading, will be examined. The high-low step loading is utilized to illustrate the effect of transient deformation on fatigue life estimation procedures, and their relationship to the observed and modeled deformation.

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