In Situ Study of the Stress Relaxation During Aging of Nickel-Base Superalloy Forgings

Aba-Perea, P.E.; Withers, Philip J.; Pirling, Thilo; Paradowska, Anna; Ma, Dong; Preuss, Michael

doi:10.1007/s11661-019-05302-0

Cited by 10 publications

(3 citation statements)

References 27 publications

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“…S4(b) in the ESM) [83,84] with an onset temperature at 400 °C. It should be noted that both T1 and T2 regions in the Au-Fe NPs are below the typical value for relaxation of the corresponding bulk materials (~ 0.6 melting point [85,86]), evidencing a sizedependent effect. Similar behavior was also observed in alloyed bulk Ag-Au at 720 °C in contrast to 200 °C for the 8 nm-sized Ag-Au NPs at the same composition [71,87].…”

Section: Resultsmentioning

confidence: 93%

Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium

et al. 2021

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Bimetallic nanoparticles are often superior candidates for a wide range of technological and biomedical applications owing to their enhanced catalytic, optical, and magnetic properties, which are often better than their monometallic counterparts. Most of their properties strongly depend on their chemical composition, crystallographic structure, and phase distribution. However, little is known of how their crystal structure, on the nanoscale, transforms over time at elevated temperatures, even though this knowledge is highly relevant in case nanoparticles are used in, e.g., high-temperature catalysis. Au-Fe is a promising bimetallic system where the low-cost and magnetic Fe is combined with catalytically active and plasmonic Au. Here, we report on the in situ temporal evolution of the crystalline ordering in Au-Fe nanoparticles, obtained from a modern laser ablation in liquids synthesis. Our in-depth analysis, complemented by dedicated atomistic simulations, includes a detailed structural characterization by X-ray diffraction and transmission electron microscopy as well as atom probe tomography to reveal elemental distributions down to a single atom resolution. We show that the Au-Fe nanoparticles initially exhibit highly complex internal nested nanostructures with a wide range of compositions, phase distributions, and size-depended microstrains. The elevated temperature induces a diffusion-controlled recrystallization and phase merging, resulting in the formation of a single face-centered-cubic ultrastructure in contact with a body-centered cubic phase, which demonstrates the metastability of these structures. Uncovering these unique nanostructures with nested features could be highly attractive from a fundamental viewpoint as they could give further insights into the nanoparticle formation mechanism under non-equilibrium conditions. Furthermore, the in situ evaluation of the crystal structure changes upon heating is potentially relevant for high-temperature process utilization of bimetallic nanoparticles, e.g., during catalysis.

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Section: Resultsmentioning

confidence: 93%

Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium

et al. 2021

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“…By combining the theoretical and creep models, they developed an analytical model and used finite element modeling to study the impact of three-stage creep on stress relaxation. [13] Additionally, YAKUI LIU et al conducted stress relaxation simulations on springs of the same type made from 60Si2CrVA that had been in use for 36 months in high-voltage circuit breakers. In stress relaxation testing, the stiffness coefficient of the spring rapidly decreased within the first 6 months, followed by a slowed descent.…”

Section: Introductionmentioning

confidence: 99%

Research on the failure and fracture factors of spring in high voltage circuit breakers

Xu,

Cheng,

Weng

et al. 2024

Fourth International Conference on Mechanical Engineering, Intelligent Manufacturing, and Automation Technology (MEMAT 2023)

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The failure of the operating spring stress in high-voltage circuit breakers, along with fatigue fracture, can result in inadequate opening and closing speeds, exceeding the specified opening and closing times, and the inability to close, seriously affecting the safe and stable operation of equipment and the power grid. In the actual production and maintenance processes, neglecting the operating conditions of the high-voltage circuit breaker spring, such as temperature, loading position, preload, motor vibration, and other factors, leads to poor estimation accuracy of the spring's fatigue state and remaining life. Additionally, the inability to accurately judge the creep and relaxation characteristics of the spring during use results in phenomena such as spring creep deformation and relaxation, leading to problems of missing maintenance opportunities. This paper focuses on studying the influence of external operating conditions, as well as creep and relaxation characteristics, on the properties of the spring. It aims to provide relevant support for the design and operation of springs in subsequent applications.

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“…The peak-aged (T6) and over-aged (T7) condition produced only about a 22.5 to 34.7% reduction in residual stresses. Aba-Perea [29] used neutron diffraction to in situ follow the evolution of residual stress of Inconel 718 during the aging process. Almost 90% of stress relaxation was found to occur primarily during heating to the aging temperature as a result of a combination of plasticity and early-stage creep relaxation.…”

Section: Introductionmentioning

confidence: 99%

Effect of Cold Pressing and Aging on Reduction and Evolution of Quenched Residual Stress for Al-Zn-Mg-Cu T-Type Rib

et al. 2021

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The preparation of the Al-Zn-Mg-Cu T-type rib consisted of forging, quenching, cold pressing, aging and the final machining processes, and the evolution of residual stress played a significant role in its properties and accuracy. Numerical models were established to investigate the evolution and distribution of residual stress for the T-type rib during the quenching and cold pressing processes. The results showed that the distribution of residual stress at the stiffened area is asymmetrical, which is different from the symmetrical distribution at the smooth area. The cold pressing is beneficial for the reduction of residual stress. The stepwise cold pressing resulted in the heterogeneous distribution of residual stress at the stiffened area and the overlap region. Three comparative T-type ribs were conducted, and their residual stresses were measured using X-ray diffraction and the contour method. A stress reduction of 50% can be obtained at the surfaces of the T-type rib through cold pressing followed by the aging process. The reduction of the maximum tensile stress at the stiffened area of the T-type rib was 42% and 50% for the cold pressing and aging, respectively, which increased to 54% and 60% at the smooth area. The mechanism of the stress reduction during the cold pressing and the aging processes was discussed.

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In Situ Study of the Stress Relaxation During Aging of Nickel-Base Superalloy Forgings

Cited by 10 publications

References 27 publications

Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium

Multidimensional thermally-induced transformation of nest-structured complex Au-Fe nanoalloys towards equilibrium

Research on the failure and fracture factors of spring in high voltage circuit breakers

Effect of Cold Pressing and Aging on Reduction and Evolution of Quenched Residual Stress for Al-Zn-Mg-Cu T-Type Rib

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