The Experts below are selected from a list of 279 Experts worldwide ranked by ideXlab platform
Soonbok Lee - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Strain Aging effect on the fatigue resistance of type 316l stainless steel
International Journal of Fatigue, 2005Co-Authors: Seonggu Hong, Keumoh Lee, Soonbok LeeAbstract:Mechanism of Dynamic Strain Aging (DSA) and its effect on the high-temperature low-cycle fatigue resistance in type 316L stainless steel were investigated by carrying out low-cycle fatigue tests in a wide temperature range from 20 to 650 8C with Strain rates of 3.2!10 K5 –1! 10 K2 /s. The regime of DSA was evaluated using the anomalous features of material behavior associated with DSA. The activation energies for each type of serration were about 0.57–0.74 times those for lattice diffusion indicating that a mechanism other than lattice diffusion is involved. It is reasonably concluded that the pipe diffusion of solute atoms along the dislocation core is responsible for DSA. Dynamic Strain Aging reduced the fatigue resistance by ways of multiple crack initiation, which comes from the DSA-induced inhomogeneity of deformation, and rapid crack propagation due to the DSA-induced hardening. q 2005 Elsevier Ltd. All rights reserved.
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the tensile and low cycle fatigue behavior of cold worked 316l stainless steel influence of Dynamic Strain Aging
International Journal of Fatigue, 2004Co-Authors: Seonggu Hong, Soonbok LeeAbstract:Abstract Tensile and low-cycle fatigue (LCF) tests were carried out in air in a wide temperature range from 20 to 750 °C and Strain rates of 1×10−4–1×10−2/s to investigate the influence of Strain rate on tensile and LCF properties of cold worked 316L stainless steel, especially in the Dynamic Strain Aging (DSA) regime. Dynamic Strain Aging caused a change in the tensile properties such as strength and ductility in the temperature range from 250 to 600 °C. This temperature range coincided well with the regime of negative Strain rate sensitivity. Cyclic stress response at all test conditions was characterized by an initial hardening during the few cycles, followed by gradual softening until failure. Temperature and Strain rate dependence on cyclic softening appears to come from a change of the cyclic plastic deformation mechanism and the DSA effect. The regimes of DSA between tensile and LCF loading conditions in terms of the negative Strain rate sensitivity were consistent with each other. At the elevated temperature, a drastic reduction in fatigue resistance was observed, and this is attributed to the effects of oxidation, creep, and Dynamic Strain Aging and interactions among these factors. The regime of DSA accelerated a reduction in fatigue resistance by enhancing crack initiation and propagation.
Seonggu Hong - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Strain Aging effect on the fatigue resistance of type 316l stainless steel
International Journal of Fatigue, 2005Co-Authors: Seonggu Hong, Keumoh Lee, Soonbok LeeAbstract:Mechanism of Dynamic Strain Aging (DSA) and its effect on the high-temperature low-cycle fatigue resistance in type 316L stainless steel were investigated by carrying out low-cycle fatigue tests in a wide temperature range from 20 to 650 8C with Strain rates of 3.2!10 K5 –1! 10 K2 /s. The regime of DSA was evaluated using the anomalous features of material behavior associated with DSA. The activation energies for each type of serration were about 0.57–0.74 times those for lattice diffusion indicating that a mechanism other than lattice diffusion is involved. It is reasonably concluded that the pipe diffusion of solute atoms along the dislocation core is responsible for DSA. Dynamic Strain Aging reduced the fatigue resistance by ways of multiple crack initiation, which comes from the DSA-induced inhomogeneity of deformation, and rapid crack propagation due to the DSA-induced hardening. q 2005 Elsevier Ltd. All rights reserved.
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the tensile and low cycle fatigue behavior of cold worked 316l stainless steel influence of Dynamic Strain Aging
International Journal of Fatigue, 2004Co-Authors: Seonggu Hong, Soonbok LeeAbstract:Abstract Tensile and low-cycle fatigue (LCF) tests were carried out in air in a wide temperature range from 20 to 750 °C and Strain rates of 1×10−4–1×10−2/s to investigate the influence of Strain rate on tensile and LCF properties of cold worked 316L stainless steel, especially in the Dynamic Strain Aging (DSA) regime. Dynamic Strain Aging caused a change in the tensile properties such as strength and ductility in the temperature range from 250 to 600 °C. This temperature range coincided well with the regime of negative Strain rate sensitivity. Cyclic stress response at all test conditions was characterized by an initial hardening during the few cycles, followed by gradual softening until failure. Temperature and Strain rate dependence on cyclic softening appears to come from a change of the cyclic plastic deformation mechanism and the DSA effect. The regimes of DSA between tensile and LCF loading conditions in terms of the negative Strain rate sensitivity were consistent with each other. At the elevated temperature, a drastic reduction in fatigue resistance was observed, and this is attributed to the effects of oxidation, creep, and Dynamic Strain Aging and interactions among these factors. The regime of DSA accelerated a reduction in fatigue resistance by enhancing crack initiation and propagation.
A.f. Armas - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Strain Aging effects on low-cycle fatigue of AISI 430F
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2009Co-Authors: Martina Avalos, I. Alvarez-armas, A.f. ArmasAbstract:Abstract The effects of Dynamic Strain Aging (DSA) on the cyclic mechanical behavior were investigated in a ferritic steel type AISI 430F. Strain-rate changes performed during cyclic tests show a negative Strain-rate dependence of the flow stress for temperatures ranging from 200 °C to 450 °C. Low-cycle fatigue curves exhibit prominent cyclic hardening at 400 °C and 450 °C. The influence of the embrittlement phenomena on the hardening of this ferritic steel was also investigated by performing Aging treatments at 400 °C and 450 °C in the alloy. These results suggest that a DSA mechanism is operative in this material in a temperature range between 300 °C and 400 °C. Stress relaxation experimental results are also discussed in terms of Dynamic Strain Aging.
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Dynamic Strain Aging influence on the cyclic behavior of zircaloy-4
Scripta Materialia, 1996Co-Authors: A.f. Armas, I. Alvarez-armas, G. MoscatoAbstract:Dynamic Strain Aging is a very important factor in the plastic deformation of zirconium and zirconium alloys and its aspects in uniaxial tensile tests have been the subject of several studies. Evidence of yield points in the stress-Strain curve, appearance of plateaus or peaks in the flow stress-temperature diagram, discontinuous plastic flow, abnormal Strain rate sensitivity have been reported in the literature. These anomalous mechanical behaviors were observed in these metals within the temperature range 473 to 823 K. The purpose of the present study is to examine the cyclic deformation characteristics of Zircaloy-4 in the temperature range 573--873 K and to show that the abnormal cyclic hardening observed in this material can be considered as a new aspect of Dynamic Strain Aging.
Hang Wang - One of the best experts on this subject based on the ideXlab platform.
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High-Temperature Low-Cycle Fatigue Behavior of HS80H Ferritic–Martensitic Steel Under Dynamic Strain Aging
Journal of Materials Engineering and Performance, 2018Co-Authors: Wenlan Wei, Yaorong Feng, Lihong Han, Jianxun Zhang, Hang WangAbstract:In this work, low-cycle fatigue tests were performed on HS80H ferritic–martensitic steel with the Strain amplitudes ranging from 0.5 to 2.0% at room temperature and 350 °C. The cyclic stress response at 350 °C was found to be different from that at room temperature due to the effect of Dynamic Strain Aging and showed a significant secondary hardening when the Strain values were 0.5 and 0.7%. Furthermore, the Dynamic Strain Aging effect also resulted in an abnormal increase in fatigue life when the Strain was 0.7%, which was due to the change in elastic Strain. Additionally, the elastic Strain and fatigue life were bilinear relations in the double logarithmic coordinates. Finally, the transmission electron microscope observations showed that the Dynamic Strain Aging led to the change in substructure, while the grain was refined.
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high temperature low cycle fatigue behavior of hs80h ferritic martensitic steel under Dynamic Strain Aging
Journal of Materials Engineering and Performance, 2018Co-Authors: Wenlan Wei, Yaorong Feng, Lihong Han, Jianxun Zhang, Hang WangAbstract:In this work, low-cycle fatigue tests were performed on HS80H ferritic–martensitic steel with the Strain amplitudes ranging from 0.5 to 2.0% at room temperature and 350 °C. The cyclic stress response at 350 °C was found to be different from that at room temperature due to the effect of Dynamic Strain Aging and showed a significant secondary hardening when the Strain values were 0.5 and 0.7%. Furthermore, the Dynamic Strain Aging effect also resulted in an abnormal increase in fatigue life when the Strain was 0.7%, which was due to the change in elastic Strain. Additionally, the elastic Strain and fatigue life were bilinear relations in the double logarithmic coordinates. Finally, the transmission electron microscope observations showed that the Dynamic Strain Aging led to the change in substructure, while the grain was refined.
Takeshi Nagase - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Strain Aging of Al0.3CoCrFeNi high entropy alloy single crystals
Scripta Materialia, 2015Co-Authors: Hiroyuki Y. Yasuda, Kyosuke Shigeno, Takeshi NagaseAbstract:Abstract Single crystals of Al0.3CoCrFeNi high entropy alloy were prepared by the floating zone method and the deformation behavior was examined. Dynamic Strain Aging accompanied by a serrated flow was found to occur in the single crystals at 873 K and 1073 K. Al atoms in the alloy played an important role in the Dynamic Strain Aging. Distinct planar slip on (1 1 1) plane was also observed in Al0.3CoCrFeNi single crystals.
