The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
William J. Weber - One of the best experts on this subject based on the ideXlab platform.
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effects of fe concentration on the ion irradiation induced defect evolution and hardening in ni fe solid solution alloys
Acta Materialia, 2016Co-Authors: Chenyang Lu, Lumin Wang, William J. Weber, Mohammad W Ullah, Jonathan D Poplawsky, Yanwen ZhangAbstract:Abstract Understanding alloying effects on the irradiation response of structural materials is pivotal in nuclear engineering. To systematically explore the effects of Fe concentration on the irradiation-induced defect evolution and hardening in face-centered cubic Ni-Fe binary solid solution alloys, single crystalline Ni-xFe (x = 0–60 at%) alloys have been grown and irradiated with 1.5 MeV Ni ions. The irradiations have been performed over a wide range of fluences from 3 × 1013 to 3 × 1016 cm−2 at room temperature. Ion channeling technique has shown reduced damage accumulation with increasing Fe concentration in the low fluence regime, which is consistent to the results from molecular dynamic simulations. No irradiation-induced compositional segregation was observed in atom probe tomography within the detection limit, even in the samples irradiated with high fluence Ni ions. Transmission electron microscopy analyses have further demonstrated that the defect size significantly decreases with increasing Fe concentration, indicating a delay in defect evolution. Furthermore, irradiation induced hardening has been measured by nanoindentation tests. Ni and the Ni-Fe alloys have largely different initial hardness, but they all follow a similar trend for the increase of hardness as a function of irradiation fluence.
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grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation
Physical Review B, 2010Co-Authors: Yanwen Zhang, William J. Weber, Philip D Edmondson, Weilin Jiang, Chongmin Wang, Fereydoon Namavar, Zihua Zhu, Fei Gao, Jie LianAbstract:Grain growth, oxygen stoichiometry, and phase stability of nanostructurally stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au-ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with irradiation dose to $\ensuremath{\sim}30\text{ }\text{nm}$ at $\ensuremath{\sim}35\text{ }\text{dpa}$. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from $\ensuremath{\sim}2.0$ for the as-deposited films to $\ensuremath{\sim}1.65$ after irradiation to $\ensuremath{\sim}35\text{ }\text{dpa}$. The loss of oxygen suggests a significant increase in oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.
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grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation
Physical Review B, 2010Co-Authors: Yanwen Zhang, William J. Weber, Philip D Edmondson, Weilin Jiang, Chongmin Wang, Fereydoon Namavar, Zihua Zhu, Fei Gao, Jie LianAbstract:Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. The loss of oxygen suggests a significant increase of oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.
Yanwen Zhang - One of the best experts on this subject based on the ideXlab platform.
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effects of fe concentration on the ion irradiation induced defect evolution and hardening in ni fe solid solution alloys
Acta Materialia, 2016Co-Authors: Chenyang Lu, Lumin Wang, William J. Weber, Mohammad W Ullah, Jonathan D Poplawsky, Yanwen ZhangAbstract:Abstract Understanding alloying effects on the irradiation response of structural materials is pivotal in nuclear engineering. To systematically explore the effects of Fe concentration on the irradiation-induced defect evolution and hardening in face-centered cubic Ni-Fe binary solid solution alloys, single crystalline Ni-xFe (x = 0–60 at%) alloys have been grown and irradiated with 1.5 MeV Ni ions. The irradiations have been performed over a wide range of fluences from 3 × 1013 to 3 × 1016 cm−2 at room temperature. Ion channeling technique has shown reduced damage accumulation with increasing Fe concentration in the low fluence regime, which is consistent to the results from molecular dynamic simulations. No irradiation-induced compositional segregation was observed in atom probe tomography within the detection limit, even in the samples irradiated with high fluence Ni ions. Transmission electron microscopy analyses have further demonstrated that the defect size significantly decreases with increasing Fe concentration, indicating a delay in defect evolution. Furthermore, irradiation induced hardening has been measured by nanoindentation tests. Ni and the Ni-Fe alloys have largely different initial hardness, but they all follow a similar trend for the increase of hardness as a function of irradiation fluence.
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grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation
Physical Review B, 2010Co-Authors: Yanwen Zhang, William J. Weber, Philip D Edmondson, Weilin Jiang, Chongmin Wang, Fereydoon Namavar, Zihua Zhu, Fei Gao, Jie LianAbstract:Grain growth, oxygen stoichiometry, and phase stability of nanostructurally stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au-ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with irradiation dose to $\ensuremath{\sim}30\text{ }\text{nm}$ at $\ensuremath{\sim}35\text{ }\text{dpa}$. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from $\ensuremath{\sim}2.0$ for the as-deposited films to $\ensuremath{\sim}1.65$ after irradiation to $\ensuremath{\sim}35\text{ }\text{dpa}$. The loss of oxygen suggests a significant increase in oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.
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grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation
Physical Review B, 2010Co-Authors: Yanwen Zhang, William J. Weber, Philip D Edmondson, Weilin Jiang, Chongmin Wang, Fereydoon Namavar, Zihua Zhu, Fei Gao, Jie LianAbstract:Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. The loss of oxygen suggests a significant increase of oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.
Philip D Edmondson - One of the best experts on this subject based on the ideXlab platform.
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helium trapping in carbide precipitates in a tempered f82h ferritic martensitic steel
Nuclear materials and energy, 2015Co-Authors: Baishakhi Mazumder, M E Bannister, F W Meyer, M K Miller, Chad M Parish, Philip D EdmondsonAbstract:Abstract The microstructural changes of a tempered F82H ferritic–martensitic steel following He implantation at 60 and 500 °C have been examined by transmission electron microscopy (TEM) and atom probe tomography (APT). After irradiation at 500 °C, numerous He bubbles were formed throughout the matrix, whereas after irradiation at 60 °C, no bubbles were seen to form in the matrix. In both irradiations, He bubbles were observed to have formed within large carbide precipitates, determined by APT compositional analysis to be M23C6. The observed preferential He bubble formation in carbides during low temperature He irradiation occurs as a result of the diffusing He being trapped in the carbide due to the strong He–C bond. As the He concentration increases in the carbide due to trapping, He bubbles are formed.
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grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation
Physical Review B, 2010Co-Authors: Yanwen Zhang, William J. Weber, Philip D Edmondson, Weilin Jiang, Chongmin Wang, Fereydoon Namavar, Zihua Zhu, Fei Gao, Jie LianAbstract:Grain growth, oxygen stoichiometry, and phase stability of nanostructurally stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au-ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with irradiation dose to $\ensuremath{\sim}30\text{ }\text{nm}$ at $\ensuremath{\sim}35\text{ }\text{dpa}$. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from $\ensuremath{\sim}2.0$ for the as-deposited films to $\ensuremath{\sim}1.65$ after irradiation to $\ensuremath{\sim}35\text{ }\text{dpa}$. The loss of oxygen suggests a significant increase in oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.
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grain growth and phase stability of nanocrystalline cubic zirconia under ion irradiation
Physical Review B, 2010Co-Authors: Yanwen Zhang, William J. Weber, Philip D Edmondson, Weilin Jiang, Chongmin Wang, Fereydoon Namavar, Zihua Zhu, Fei Gao, Jie LianAbstract:Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized cubic zirconia (NSZ) are investigated under 2 MeV Au ion bombardment at 160 and 400 K to doses up to 35 displacements per atom (dpa). The NSZ films are produced by ion-beam-assisted deposition technique at room temperature with an average grain size of 7.7 nm. The grain size increases with dose, and follows a power law (n=6) to a saturation value of ~30 nm that decreases with temperature. Slower grain growth is observed under 400 K irradiations, as compared to 160 K irradiations, indicating that the grain growth is not thermally activated and irradiation-induced grain growth is the dominating mechanism. While the cubic structure is retained and no new phases are identified after the high-dose irradiations, oxygen reduction in the irradiated NSZ films is detected. The ratio of O to Zr decreases from ~2.0 for the as-deposited films to ~1.65 after irradiation to ~35 dpa. The loss of oxygen suggests a significant increase of oxygen vacancies in nanocrystalline zirconia under ion irradiation. The oxygen deficiency may be essential in stabilizing the cubic phase to larger grain sizes.
Elie Paccou - One of the best experts on this subject based on the ideXlab platform.
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irradiation assisted stress corrosion cracking susceptibility and mechanical properties related to irradiation induced microstructures of 304l austenitic stainless steel
Journal of Nuclear Materials, 2020Co-Authors: Elie Paccou, Benoit Tanguy, Marc LegrosAbstract:Abstract 304L SSs are used for structural components of Light Water Reactor (LWR) nuclear power plants and have been shown to face Irradiation Assisted Stress Corrosion Cracking (IASCC). This degradation phenomenon has been of great concern regarding structural integrity of reactors for lifetime extension of LWRs but is still not completely understood. This study evaluates the evolution of mechanical properties (hardening) and susceptibility to stress corrosion cracking regarding different radiation induced microstructures. These microstructures were chosen to explore representative conditions encountered in Pressure Water Reactor (PWRs) conditions but also the effect of various populations of cavities as extreme case of those reported at higher flux and temperature. Irradiation microstructures are produced by heavy ions irradiation under two different temperatures (450 °C and 600 °C) and with or without helium implantation. The evolution of microstructure, hardness and cracking susceptibility are characterized after irradiation. Calculations based on defects population are found to be in agreement with hardening measurement for irradiations with no helium implantation only. Cracking susceptibilities are characterized after slow strain rate tests performed at 4% plastic strain under PWR environment. Cracking susceptibility changes for different irradiations and quantitative assessment of the effect of irradiation microstructure on IASCC phenomenon is discussed.
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irradiation assisted stress corrosion cracking susceptibility and mechanical properties related to irradiation induced microstructures of 304l austenitic stainless steel
Journal of Nuclear Materials, 2020Co-Authors: Elie Paccou, Benoit Tanguy, Marc LegrosAbstract:Abstract 304L SSs are used for structural components of Light Water Reactor (LWR) nuclear power plants and have been shown to face Irradiation Assisted Stress Corrosion Cracking (IASCC). This degradation phenomenon has been of great concern regarding structural integrity of reactors for lifetime extension of LWRs but is still not completely understood. This study evaluates the evolution of mechanical properties (hardening) and susceptibility to stress corrosion cracking regarding different radiation induced microstructures. These microstructures were chosen to explore representative conditions encountered in Pressure Water Reactor (PWRs) conditions but also the effect of various populations of cavities as extreme case of those reported at higher flux and temperature. Irradiation microstructures are produced by heavy ions irradiation under two different temperatures (450 °C and 600 °C) and with or without helium implantation. The evolution of microstructure, hardness and cracking susceptibility are characterized after irradiation. Calculations based on defects population are found to be in agreement with hardening measurement for irradiations with no helium implantation only. Cracking susceptibilities are characterized after slow strain rate tests performed at 4% plastic strain under PWR environment. Cracking susceptibility changes for different irradiations and quantitative assessment of the effect of irradiation microstructure on IASCC phenomenon are discussed.
Marc Legros - One of the best experts on this subject based on the ideXlab platform.
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irradiation assisted stress corrosion cracking susceptibility and mechanical properties related to irradiation induced microstructures of 304l austenitic stainless steel
Journal of Nuclear Materials, 2020Co-Authors: Elie Paccou, Benoit Tanguy, Marc LegrosAbstract:Abstract 304L SSs are used for structural components of Light Water Reactor (LWR) nuclear power plants and have been shown to face Irradiation Assisted Stress Corrosion Cracking (IASCC). This degradation phenomenon has been of great concern regarding structural integrity of reactors for lifetime extension of LWRs but is still not completely understood. This study evaluates the evolution of mechanical properties (hardening) and susceptibility to stress corrosion cracking regarding different radiation induced microstructures. These microstructures were chosen to explore representative conditions encountered in Pressure Water Reactor (PWRs) conditions but also the effect of various populations of cavities as extreme case of those reported at higher flux and temperature. Irradiation microstructures are produced by heavy ions irradiation under two different temperatures (450 °C and 600 °C) and with or without helium implantation. The evolution of microstructure, hardness and cracking susceptibility are characterized after irradiation. Calculations based on defects population are found to be in agreement with hardening measurement for irradiations with no helium implantation only. Cracking susceptibilities are characterized after slow strain rate tests performed at 4% plastic strain under PWR environment. Cracking susceptibility changes for different irradiations and quantitative assessment of the effect of irradiation microstructure on IASCC phenomenon is discussed.
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irradiation assisted stress corrosion cracking susceptibility and mechanical properties related to irradiation induced microstructures of 304l austenitic stainless steel
Journal of Nuclear Materials, 2020Co-Authors: Elie Paccou, Benoit Tanguy, Marc LegrosAbstract:Abstract 304L SSs are used for structural components of Light Water Reactor (LWR) nuclear power plants and have been shown to face Irradiation Assisted Stress Corrosion Cracking (IASCC). This degradation phenomenon has been of great concern regarding structural integrity of reactors for lifetime extension of LWRs but is still not completely understood. This study evaluates the evolution of mechanical properties (hardening) and susceptibility to stress corrosion cracking regarding different radiation induced microstructures. These microstructures were chosen to explore representative conditions encountered in Pressure Water Reactor (PWRs) conditions but also the effect of various populations of cavities as extreme case of those reported at higher flux and temperature. Irradiation microstructures are produced by heavy ions irradiation under two different temperatures (450 °C and 600 °C) and with or without helium implantation. The evolution of microstructure, hardness and cracking susceptibility are characterized after irradiation. Calculations based on defects population are found to be in agreement with hardening measurement for irradiations with no helium implantation only. Cracking susceptibilities are characterized after slow strain rate tests performed at 4% plastic strain under PWR environment. Cracking susceptibility changes for different irradiations and quantitative assessment of the effect of irradiation microstructure on IASCC phenomenon are discussed.
