Study on hot deformation behavior and numerical simulation for hot extrusion process of corrosion resistant 825 alloy

Liu, Yang; Geng, Zhiyu; Zhang, Maicang; Dong, Jie

doi:10.1016/j.proeng.2011.12.547

Cited by 7 publications

(5 citation statements)

References 2 publications

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“…The activation energy value for the deformation of alloy B was found to be higher than that of Alloy A. In addition, previous studies using the same methods reported activation energies of 438 kJ mol −1 [53] and 416 kJ mol −1 [54], which are in good agreement with the values from the current study. For alloy 825 (as used in the current study), the constitutive equations may also be expressed as Equations ( 11) and (12), where the subscript A and B refer to the alloys in the current study, all other symbols have the meanings previously defined and the peak stress is given in megapascal [52]:…”

Section: Modelling Of Flow Stress and Microstructural Behavior 431 Determination Of Materials Constantssupporting

confidence: 91%

“…The average value of H for alloy A and alloy B are equal to 430 and 450 kJ mol −1 , respectively. This matches very well with some other superalloys obtained through different methodologies (from 416 to 486 kJ mol −1 , Table 4) [38,39,[53][54][55][56][57][58]. ε and log 10 [sinh(ασ P )] at a constant deformation temperature, and (b) the decadic logarithm of the product of peak stress and the parameter, α, log 10 [sinh(ασ P )] and the inverse of absolute temperature, T −1 , at a constant strain rate.…”

Section: Modelling Of Flow Stress and Microstructural Behavior 431 Determination Of Materials Constantssupporting

confidence: 89%

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Effect of Trace Magnesium Additions on the Dynamic Recrystallization in Cast Alloy 825 after One-Hit Hot-Deformation

Al-Saadi

Hulme-Smith

et al. 2020

Metals

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Alloy 825 is widely used in several industries, but its useful service life is limited by both mechanical properties and corrosion resistance. The current work explores the effect of the addition of magnesium on the recrystallization and mechanical behavior of alloy 825 under hot compression. Compression tests were performed under conditions representative of typical forming processes: temperatures between 1100 and 1250 °C and at strain rates of 0.1–10 s−1 to a true strain of 0.7. Microstructural evolution was characterized by electron backscattered diffraction. Dynamic recrystallization was found to be more prevalent under all test conditions in samples containing magnesium, but not in all cases of conventional alloy 825. The texture direction ⟨101⟩ was the dominant orientation parallel to the longitudinal direction of casting (also the direction in which the samples were compressed) in samples that contained magnesium under all test conditions, but not in any sample that did not contain magnesium. For all deformation conditions, the peak stress was approximately 10% lower in material with the addition of magnesium. Furthermore, the differences in the peak strain between different temperatures are approximately 85% smaller if magnesium is present. The average activation energy for hot deformation was calculated to be 430 kJ mol−1 with the addition of magnesium and 450 kJ mol−1 without magnesium. The average size of dynamically recrystallized grains in both alloys showed a power law relation with the Zener–Hollomon parameter, DD~Z−n, and the exponent of value, n, is found to be 0.12. These results can be used to design optimized compositions and thermomechanical treatments of alloy 825 to maximize the useful service life under current service conditions. No experiments were conducted to investigate the effects of such changes on the service life and such experiments should now be performed.

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Section: Modelling Of Flow Stress and Microstructural Behavior 431 Determination Of Materials Constantssupporting

confidence: 91%

Section: Modelling Of Flow Stress and Microstructural Behavior 431 Determination Of Materials Constantssupporting

confidence: 89%

Effect of Trace Magnesium Additions on the Dynamic Recrystallization in Cast Alloy 825 after One-Hit Hot-Deformation

Al-Saadi

Hulme-Smith

et al. 2020

Metals

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“…[ 138,140 ] Moreover, ion intercalation and similar chemical exfoliation are widely used for the fabrication of 2D TE nanofilm materials. [ 68,141–143 ] Jiang et al. [ 142 ] reported organic solvent‐assisted exfoliated MoS 2 to improve the TE performance of the PEDOT:PSS film.…”

Section: Fabrication and Design Of Wearable Thermoelectric Generatorsmentioning

confidence: 99%

Wearable Thermoelectric Materials and Devices for Self‐Powered Electronic Systems

et al. 2021

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Because of their readiness and high power bandwidth, batteries are the preeminent source of power supply for portable electronics, but are subject to periodic recharging and replacement. Hence, a key challenge is to design suitable and sustainable power sources for portable electronic devices. Harvesting energy from the human body is suitable for providing consistent and uninterrupted energy for wearable electronic devices. The daily activities of a 68-kg adult can generate over 100 W of power, through breathing, heating, blood transport, and walking. [3] Thus, converting 1% of the power generated by the human body may be enough to support the work of most portable electronics. Various energy-harvesting technologies, such as, triboelectric nanogenerators (TENGs), [4][5][6] piezoelectric nanogenerators, [7] and thermoelectric generators (TEGs), [8] have been developed to convert human energy (from human motion and body heat) into electricity. In line with recent developments in wearable electronics and e-skins, the use of a self-powered direct-current (DC) electric power supplier is inevitable for activating human body-adjustable electronic systems. [9] Among the various energy-autonomous devices, [10] only TEGs can permanently produce DC electric power without complex power managing components, and they are maintenance free. Moreover, solar energy and vibration-based energy harvesters areThe emergence of artificial intelligence and the Internet of Things has led to a growing demand for wearable and maintenance-free power sources. The continual push toward lower operating voltages and power consumption in modern integrated circuits has made the development of devices powered by body heat finally feasible. In this context, thermoelectric (TE) materials have emerged as promising candidates for the effective conversion of body heat into electricity to power wearable devices without being limited by environmental conditions. Driven by rapid advances in processing technology and the performance of TE materials over the past two decades, wearable thermoelectric generators (WTEGs) have gradually become more flexible and stretchable so that they can be used on complex and dynamic surfaces. In this review, the functional materials, processing techniques, and strategies for the device design of different types of WTEGs are comprehensively covered. Wearable self-powered systems based on WTEGs are summarized, including multi-function TE modules, hybrid energy harvesting, and all-in-one energy devices. Challenges in organic TE materials, interfacial engineering, and assessments of device performance are discussed, and suggestions for future developments in the area are provided. This review will promote the rapid implementation of wearable TE materials and devices in self-powered electronic systems.The ORCID identification number(s) for the author(s) of this article can be found under https://doi.org/10.1002/adma.202102990.

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“…This is due to changes that occur during thermomechanical processing of the billet that lead to a sub-optimum grain size distribution and precipitate population. In forged products of Alloy 825, work hardening, recovery, and recrystallization are possible during hotforging and soft annealing [8,[14][15][16][17][18][19]. It is well known that recrystallization generates fine grains, which are beneficial for both strength and toughness [20][21][22].…”

Section: Introductionmentioning

confidence: 99%

Modelling of Strengthening Mechanisms in Wrought Nickel-Based 825 Alloy Subjected to Solution Annealing

Al-Saadi

Sandberg

Jönsson

et al. 2021

Metals

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Wrought nickel-based Alloy 825 is widely used in the oil and gas industries, attributed to its high strength at temperatures up to 540 °C. However, differences in mechanical properties arise in finished components due to variations in both grain size and dislocation density. Numerous experimental studies of the strengthening mechanisms have been reported and many models have been developed to predict strengthening under thermomechanical processing. However, there are debates surrounding some fundamental issues in modeling and the interpretation of experimental observations. Therefore, it is important to understand the evolution of strain within the material during the hot-forging process. In addition, there is a lack of research around the behavior during hot deformation and subsequent stabilization of Alloy 825. This article investigates the origin of this strength and considers a variety of strengthening mechanisms, resulting in a quantitative prediction of the contribution of each mechanism. The alloy is processed with a total forging strain of 0.45, 0.65, or 0.9, and subsequent annealing at a temperature of 950 °C, reflecting commercial practice. The microstructure after annealing is similar to that before annealing, suggesting that static recovery is dominant at this temperature. The maximum yield strength and ultimate tensile strength were 348 MPa and 618 MPa, respectively, obtained after forging to a true strain of 0.9, with a ductility of 40%. The majority of strengthening was attributed to grain refinement, the dislocation densities that arise due to the large forging strain deformation, and solid solution strengthening. Precipitate strengthening was also quantified using the Brown and Ham modification of the Orowan bowing model. The results of yield strength calculations are in excellent agreement with experimental data, with less than 1% difference. The interfacial energy of Ti(C,N) in the face-centered cubic matrix of the current alloy has been assessed for the first time, with a value of 0.8 mJm−2. These results can be used by future researchers and industry to predict the strength of Alloy 825 and similar alloys, especially after hot-forging.

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Study on hot deformation behavior and numerical simulation for hot extrusion process of corrosion resistant 825 alloy

Cited by 7 publications

References 2 publications

Effect of Trace Magnesium Additions on the Dynamic Recrystallization in Cast Alloy 825 after One-Hit Hot-Deformation

Effect of Trace Magnesium Additions on the Dynamic Recrystallization in Cast Alloy 825 after One-Hit Hot-Deformation

Wearable Thermoelectric Materials and Devices for Self‐Powered Electronic Systems

Modelling of Strengthening Mechanisms in Wrought Nickel-Based 825 Alloy Subjected to Solution Annealing

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