The Experts below are selected from a list of 3465 Experts worldwide ranked by ideXlab platform
Hamilton Ferreira Gomes De Abreu - One of the best experts on this subject based on the ideXlab platform.
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role of crystallographic texture on the improvement of hydrogen induced crack resistance in api 5l x70 pipeline steel
International Journal of Hydrogen Energy, 2017Co-Authors: Mohammad Masoumi, Cleiton Carvalho Silva, Miloslav Beres, Duberney Hincapie Ladino, Hamilton Ferreira Gomes De AbreuAbstract:Abstract The purpose of this work was to improve the resistance of hydrogen-induced cracking in API 5L X70 steel by engineering the crystallographic texture and grain boundary distributions via different rolling temperatures. Hydrogen-induced cracking and electrochemical hydrogen charging tests were carried out in two different conditions: commercially produced and isothermally Rolled at 850 °C in laboratory. The results showed that the development of dominant {011} grains parallel to the normal direction, and a small number of {001}//ND grains obtained by isothermal rolling at 850 °C, increased the hydrogen-induced crack resistance; while the hot Rolled Sample with sharp {001}//ND textures was highly susceptible to cracking.
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effect of rolling in the recrystallization temperature region associated with a post heat treatment on the microstructure crystal orientation and mechanical properties of api 5l x70 pipeline steel
Materials Research-ibero-american Journal of Materials, 2016Co-Authors: Mohammad Masoumi, Cleiton Carvalho Silva, Hamilton Ferreira Gomes De AbreuAbstract:In order to improve the mechanical properties of API X70 pipeline steel, a rolling schedule in the recrystallization temperature region associated with a post heat treatment was proposed. Optical and scanning electron microscopy, electron backscattered diffraction, hardness, and tensile tests were carried out to show the effects of microstructure and crystallographic orientation on the final mechanical properties. The normalized hot-Rolled Sample and the Sample subjected to hot-rolling followed by quenching and consequent tempering at 700 °C exhibited an excellent combination of yield strength and elongation. This was attributed to the recrystallized ferrite microstructure and tempered martensite with martensite–austenite constituent dispersion, respectively. In addition, the development of (112)[111] and (111)[101] texture components and the high fraction of low angle boundaries have a significant effect on the improvement of the mechanical properties.Keywords:
Xuefei Chen - One of the best experts on this subject based on the ideXlab platform.
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Grain Refinement and Aging Hardening of the Mg-10Gd-3Y-2Ag-0.4Zr Alloy Produced by a Two-Step Forming Process
Materials, 2018Co-Authors: Huiyan Ning, Yandong Yu, Lirong Xiao, Li Li, Xuefei ChenAbstract:Grain refinement and precipitation are two effective ways to improve the mechanical properties of Mg-RE alloys. In this work, a two-step forming process is proposed. This includes cold rolling and subsequent annealing at high temperature for a short duration. By the two-step forming process, grains can be refined from 100 μm to 20 μm in compare with ~30 μm by common hot rolling at 450 °C for a reduction of 80%. The Sample shows more distinct aging hardening, as the hardness amplification of 60 HV is twice that of the hot-Rolled Sample. The precipitation is observed by high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). Dynamic precipitation in the Sample by the two-step route is found to be effectively suppressed. Interestingly, after subsequent annealing, the density of precipitation, especially β′, become much higher than that in hot-Rolled Samples.
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Grain Refinement and Aging Hardening of the Mg-10Gd-3Y-2Ag-0.4Zr Alloy Produced by a Two-Step Forming Process
MDPI AG, 2018Co-Authors: Huiyan Ning, Lirong Xiao, Bo Gao, Lihua Wen, Zehua Yan, Xuefei ChenAbstract:Grain refinement and precipitation are two effective ways to improve the mechanical properties of Mg-RE alloys. In this work, a two-step forming process is proposed. This includes cold rolling and subsequent annealing at high temperature for a short duration. By the two-step forming process, grains can be refined from 100 μm to 20 μm in compare with ~30 μm by common hot rolling at 450 °C for a reduction of 80%. The Sample shows more distinct aging hardening, as the hardness amplification of 60 HV is twice that of the hot-Rolled Sample. The precipitation is observed by high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). Dynamic precipitation in the Sample by the two-step route is found to be effectively suppressed. Interestingly, after subsequent annealing, the density of precipitation, especially β′, become much higher than that in hot-Rolled Samples
Hua Zhang - One of the best experts on this subject based on the ideXlab platform.
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effect of electropulsing treatment on static recrystallization behavior of cold Rolled magnesium alloy zk60 with different reductions
Journal of Materials Science & Technology, 2019Co-Authors: Huijun Guo, Xun Zeng, Jianfeng Fan, Hua Zhang, Qiang Zhang, Hongbiao DongAbstract:Abstract Effect of electropulsing treatment (EPT) on recrystallization behavior of cold-Rolled Mg alloy ZK60 strips was investigated. It was found that EPT significantly improved nucleation rate and migration ability of grain boundaries, leading to accelerated recrystallization of the deformed metals at relatively low temperature. After the recrystallization induced by EPT, the average grain size of 20% rolling reduction Samples decreased from 113 μm to around 10 μm, meanwhile the typical basal-type texture of the cold-Rolled Sample was weakened. EPT was normally accompanied with a thermal and an athermal effects. The athermal effect played a dominated role in increasing nucleation rate, while the thermal effect promoted grain growth. A fewer recrystallized grains originated along the grain boundaries in the 10% reduction Samples, while most of the recrystallization took place inside the twins in the 20% reduction Samples.
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improved mechanical properties of az31 magnesium alloy sheets by repeated cold rolling and annealing using a small pass reduction
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Hua Zhang, Jianfeng Fan, Weili Cheng, Hongbiao DongAbstract:Abstract Much less attention has been paid to improve the mechanical properties of magnesium alloy by cold rolling due to its poor room temperature workability. So the present work attempts to improve the mechanical properties of AZ31 magnesium alloy sheets processed by repeated cold rolling and annealing using a small pass reduction in correlation with the concurrent microstructure evolution. The obtained results indicated that after 87% total repeated cold rolling reduction and annealing, the grain microstructure of AZ31 alloy sheet was successfully refined from 22.3 μm to 7.4 μm. The alternating change induced by repeated cold rolling and annealing between deformed microstructure and recrystallized microstructure resulted in the continued refinement of grains. After repeated cold rolling and annealing, the mechanical properties of AZ31 alloy sheets were improved, especially the Erichsen value (IE) of the 87% total Rolled Sample in annealed condition was significantly increased by more than 36% compared to that of the as-received Sample under the same thickness. Improving mechanical properties of AZ31 alloy sheets processed by repeated cold rolling and annealing are ascribed to the grain refinement and weakened basal texture. Finally, 0.40 mm thick thin sheets with good comprehensive mechanical properties were obtained by repeated cold rolling and annealing using a small pass reduction.
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improving low cycle fatigue properties of Rolled az31 magnesium alloy by pre compression deformation
Materials & Design, 2014Co-Authors: Guangsheng Huang, Jinhan Li, Hua ZhangAbstract:Abstract The effect of pre-compression deformation on the low-cycle fatigue properties and cyclic deformation behavior of as-Rolled AZ31 alloy was investigated by performing the stress-contRolled low-cycle fatigue tests at room temperature. Fatigue properties and cyclic damage process should be closely related to the twins. The present work aimed to investigate the deformation mechanism and fatigue life caused by the introduced {1 0−1 2} twinning–detwinning from the viewpoint of stress amplitude. The results reveal that the twins contribute to the fatigue properties and cyclic damage process of AZ31 alloy. There were noticeable changes in hysteresis loops, microstructures and fatigue lives when the stress amplitude increased from 120 to 150 MPa. The fatigue life of pre-compressed Samples was more superior to that of the as-Rolled Sample under different stress amplitudes, especially under the stress amplitude close to the tensile yield strength of the as-Rolled Sample.
Mohammad Masoumi - One of the best experts on this subject based on the ideXlab platform.
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role of crystallographic texture on the improvement of hydrogen induced crack resistance in api 5l x70 pipeline steel
International Journal of Hydrogen Energy, 2017Co-Authors: Mohammad Masoumi, Cleiton Carvalho Silva, Miloslav Beres, Duberney Hincapie Ladino, Hamilton Ferreira Gomes De AbreuAbstract:Abstract The purpose of this work was to improve the resistance of hydrogen-induced cracking in API 5L X70 steel by engineering the crystallographic texture and grain boundary distributions via different rolling temperatures. Hydrogen-induced cracking and electrochemical hydrogen charging tests were carried out in two different conditions: commercially produced and isothermally Rolled at 850 °C in laboratory. The results showed that the development of dominant {011} grains parallel to the normal direction, and a small number of {001}//ND grains obtained by isothermal rolling at 850 °C, increased the hydrogen-induced crack resistance; while the hot Rolled Sample with sharp {001}//ND textures was highly susceptible to cracking.
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effect of rolling in the recrystallization temperature region associated with a post heat treatment on the microstructure crystal orientation and mechanical properties of api 5l x70 pipeline steel
Materials Research-ibero-american Journal of Materials, 2016Co-Authors: Mohammad Masoumi, Cleiton Carvalho Silva, Hamilton Ferreira Gomes De AbreuAbstract:In order to improve the mechanical properties of API X70 pipeline steel, a rolling schedule in the recrystallization temperature region associated with a post heat treatment was proposed. Optical and scanning electron microscopy, electron backscattered diffraction, hardness, and tensile tests were carried out to show the effects of microstructure and crystallographic orientation on the final mechanical properties. The normalized hot-Rolled Sample and the Sample subjected to hot-rolling followed by quenching and consequent tempering at 700 °C exhibited an excellent combination of yield strength and elongation. This was attributed to the recrystallized ferrite microstructure and tempered martensite with martensite–austenite constituent dispersion, respectively. In addition, the development of (112)[111] and (111)[101] texture components and the high fraction of low angle boundaries have a significant effect on the improvement of the mechanical properties.Keywords:
Hongbiao Dong - One of the best experts on this subject based on the ideXlab platform.
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effect of electropulsing treatment on static recrystallization behavior of cold Rolled magnesium alloy zk60 with different reductions
Journal of Materials Science & Technology, 2019Co-Authors: Huijun Guo, Xun Zeng, Jianfeng Fan, Hua Zhang, Qiang Zhang, Hongbiao DongAbstract:Abstract Effect of electropulsing treatment (EPT) on recrystallization behavior of cold-Rolled Mg alloy ZK60 strips was investigated. It was found that EPT significantly improved nucleation rate and migration ability of grain boundaries, leading to accelerated recrystallization of the deformed metals at relatively low temperature. After the recrystallization induced by EPT, the average grain size of 20% rolling reduction Samples decreased from 113 μm to around 10 μm, meanwhile the typical basal-type texture of the cold-Rolled Sample was weakened. EPT was normally accompanied with a thermal and an athermal effects. The athermal effect played a dominated role in increasing nucleation rate, while the thermal effect promoted grain growth. A fewer recrystallized grains originated along the grain boundaries in the 10% reduction Samples, while most of the recrystallization took place inside the twins in the 20% reduction Samples.
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improved mechanical properties of az31 magnesium alloy sheets by repeated cold rolling and annealing using a small pass reduction
Materials Science and Engineering A-structural Materials Properties Microstructure and Processing, 2015Co-Authors: Hua Zhang, Jianfeng Fan, Weili Cheng, Hongbiao DongAbstract:Abstract Much less attention has been paid to improve the mechanical properties of magnesium alloy by cold rolling due to its poor room temperature workability. So the present work attempts to improve the mechanical properties of AZ31 magnesium alloy sheets processed by repeated cold rolling and annealing using a small pass reduction in correlation with the concurrent microstructure evolution. The obtained results indicated that after 87% total repeated cold rolling reduction and annealing, the grain microstructure of AZ31 alloy sheet was successfully refined from 22.3 μm to 7.4 μm. The alternating change induced by repeated cold rolling and annealing between deformed microstructure and recrystallized microstructure resulted in the continued refinement of grains. After repeated cold rolling and annealing, the mechanical properties of AZ31 alloy sheets were improved, especially the Erichsen value (IE) of the 87% total Rolled Sample in annealed condition was significantly increased by more than 36% compared to that of the as-received Sample under the same thickness. Improving mechanical properties of AZ31 alloy sheets processed by repeated cold rolling and annealing are ascribed to the grain refinement and weakened basal texture. Finally, 0.40 mm thick thin sheets with good comprehensive mechanical properties were obtained by repeated cold rolling and annealing using a small pass reduction.
