The refining effect of Al3Ti1B1RE master alloy on Al sheets used for pressure can manufacture and the behavior of mixed rare earths in master alloy were investigated with XRD, OM, SEM and EDAX. It is found that the r...The refining effect of Al3Ti1B1RE master alloy on Al sheets used for pressure can manufacture and the behavior of mixed rare earths in master alloy were investigated with XRD, OM, SEM and EDAX. It is found that the refining effect of the refiner on the material has superiority over foreign or domestic Al5Ti1B refiner, and the refiner still retains its refining ability for 6 h after adding it to molten Al, thus improving the strength and plasticity of the material remarkably. The excellent refining effect and stability of AlTiBRE refiner result from that RE can lower the surface energy of molten Al and improve the wetting characteristics of molten Al on refinement nuclei such as TiAl 3, TiB 2, etc., thus giving full play to the effect of heterogeneous nucleation and impeding the congregating tendency of TiB 2 phase in molten Al. At the same time, RE gathering in front of solid/liquid interface are also easy to cause composition supercooling in molten Al, thus impeding the growth of α Al grains and promoting α Al nucleation on refinement nuclei. In addition, RE also play certain role in purification and grain refinement, or modification, especially their effect of purification can improve the metallurgical quality of AlTiBRE master alloy.展开更多
We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surf...We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.展开更多
The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynam...The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynamic hot-simulation testing machine. The results show that the AI sheets possess the remarkable characteristic of steady state flow stress when they are deformed in the temperature range of 350-500℃ at strain rates within the range of 0.01-10.0s^-1. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature, which implies that the process of plastic deformation at elevated temperature for this material is thermally activated. Compared with the AI pieces prepared by no or conventional melt-treatment, hot deformation activation energy of AI sheets prepared by high-efficient melt-treatment is the smallest ( Q= 168.0kJ/mol), which reveals that the hot working formability of this material is very better, and has directly to do with the effective improvement of its metallurgical quality.展开更多
The effects of an electric field on AIN precipitation and recrystallization texture were investigated. Cold-rolled 08Al killed steel sheets were annealed at 550℃ according to the two-step processes, for various maint...The effects of an electric field on AIN precipitation and recrystallization texture were investigated. Cold-rolled 08Al killed steel sheets were annealed at 550℃ according to the two-step processes, for various maintaining times, with and without applying an electric field. It was found that the electric field promotes the precipitation of the second phase (AlN particles), strengthens the γ-fiber and weakens the α-fiber texture component in the recrystallized specimens. A possible explanation for the reinforcement of γ-fiber texture by the electric field is that the second phase AIN particle promotes the growth of γ-fiber at the expense of differently oriented grains.展开更多
The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and exper...The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and experiments. By comparing the numerical analyses with the experiments, a proper numerical model was obtained. From the results of the numerical analyses and the experiments, the effects of process parameters on entrance diameters of drilled holes, shapes of the holes, taper angles of the holes and temperature distributions in the vicinity of the holes were examined quantitatively. In addition, the optimal drilling condition was estimated to improve the quality of the drilled holes.展开更多
Al coated steel sheets with excellent heat resistance,thermal reflection,and corrosion resistance are widely used in various applications.The laser weldability of the Al coated steel sheet for full penetration welding...Al coated steel sheets with excellent heat resistance,thermal reflection,and corrosion resistance are widely used in various applications.The laser weldability of the Al coated steel sheet for full penetration welding was reported.The phenomenon caused by intermixed aluminum and behavior of aluminum in the weld were investigated.Al coated steel sheets that have various thickness and coating mass were prepared for laser welding.The effects of parameters such as welding conditions and Al coating conditions were investigated.Al content mixed in the weld after laser welding was evaluated,and then a correlation between the mixed Al and mechanical properties was investigated.The results show that the Al-rich zones which have Fe-Al intermetallic compounds are found in the weld.The intermetallic compounds cause the decreased strength of the weld.展开更多
The effects of variation of Mg content on microstructures, the tensile properties and the formability of Al-Mg-Si-Cu alloys for automotive body sheets were investigated by means of scan electron microscopy, optical me...The effects of variation of Mg content on microstructures, the tensile properties and the formability of Al-Mg-Si-Cu alloys for automotive body sheets were investigated by means of scan electron microscopy, optical metallographic analysis, tensile and Ericsson tests. The results show that for Al-Mg-Si-Cu aluminium alloys with excessive Si, with an increment of Mg content, the strength enhances, the specific elongation and Erisson values of alloys decrease, and the number of Mg2Si constituent increases and that of Al(MnFe)Si type constituents reduces. Al-Mg-Si-Cu aluminium alloys with excessive Si for automotive body sheets can present obviously the paint bake hardenability during the paint bake cycle (i.e. artificial aging at 170 ℃ for 30 min immediately after the solution treatment and quenching). Suitable Mg content should be controlled in the range of 0.8% and 1.2%(mass fraction).展开更多
Ti-Al thin sheet with dimension of 450 mm×450 mm×0.2 mm was prepared by electron beam physical vapor deposition(EB-PVD) technology. The surface and cross-section pattern of as-deposited sample were studied b...Ti-Al thin sheet with dimension of 450 mm×450 mm×0.2 mm was prepared by electron beam physical vapor deposition(EB-PVD) technology. The surface and cross-section pattern of as-deposited sample were studied by SEM and AFM,and then the composition and phase were analysed by XRD and EPMA. Finally,the effect on deposit by re-evaporation of Al was explored by calculating the ratio of re-evaporating capacity with depositing capacity of Al on the substrate. The results indicate that the evaporation process with Nb addition into the molten pool makes it earlier to reach the steady-state. The existing equiaxed crystal and columnar crystal along the cross-sectional may be caused by the transformation latent heat released during the transition course of atoms from gaseous state to solid state. The effect on deposit by re-evaporation of Al can be neglected because the re-evaporating capacity of Al is far below that of the depositing capacity.展开更多
In this paper, the orientation of grains which adjacent to a developed opening crack was investigated by EBSD. A definition of θ has been came up with which represents the angle between the principal stress plane and...In this paper, the orientation of grains which adjacent to a developed opening crack was investigated by EBSD. A definition of θ has been came up with which represents the angle between the principal stress plane and each plane of the grains. Smaller θ means easier to crack. It gave a good explanation of the crack propagation throughout the grains. It also revealed that propagation path is along with the plane. This finding will give a prediction of tear properties and help us understanding the cracking mechanism and the behavior of tearing.展开更多
The effects of Sr element on the forming properties of the Al-Mg-Si based alloy sheets were studied by tensile test, metallograph, DSC, XRD, SEM and TEM. The results show that the tensile strength of aluminum alloy sh...The effects of Sr element on the forming properties of the Al-Mg-Si based alloy sheets were studied by tensile test, metallograph, DSC, XRD, SEM and TEM. The results show that the tensile strength of aluminum alloy sheet added 0.033%(mass fraction)Sr increases comparing with that of free Sr. Simultaneously, the forming properties of sheets evidently increase, the elongation hardenability (n) and plastic strain ratio (r) and Erichsen number increase 27.8%, 11.1%, 10.8% and 12%, respectively, and the forming limit diagram increases evidently, too. The analysis shows that Sr is surface active element, which can refine grains of alloys, promote precipitation, reduce activation energy ofβ' phase, and lead the formation ofα-(Al8Fe2Si) phase instead ofβ-(Al5FeSi) phase. As a result, the forming properties of the alloy sheet increase.展开更多
通过拉伸和埃里克森实验以及扫描电镜/能谱、透射电镜和金相分析,研究Mn的质量分数对Al Mg Si Cu铝合金汽车板显微组织、力学性能和成形性的影响·研究表明,随Mn质量分数增加,Al Mg Si Cu汽车板铝合金不可溶结晶相及弥散相粒子数量...通过拉伸和埃里克森实验以及扫描电镜/能谱、透射电镜和金相分析,研究Mn的质量分数对Al Mg Si Cu铝合金汽车板显微组织、力学性能和成形性的影响·研究表明,随Mn质量分数增加,Al Mg Si Cu汽车板铝合金不可溶结晶相及弥散相粒子数量均增加,不可溶结晶相使合金组织纤维化对板材冲压成形性不利,弥散相粒子阻碍再结晶晶粒长大;提高Mn的质量分数,Al Mg Si Cu汽车板铝合金的强度增加,但延伸率和冲压成形性降低·展开更多
通过实验室25 kg真空感应炉冶炼和锻轧研究了0.26%~0.95%Al含量对0.5 mm 2.2%Si无取向硅钢冷轧板组织、织构和磁性能的影响。试验结果表明,0.26%~0.81%Al含量时,随钢中Al含量的增加,成品退火钢板的晶粒尺寸增加同时铁损减少;当Al含量...通过实验室25 kg真空感应炉冶炼和锻轧研究了0.26%~0.95%Al含量对0.5 mm 2.2%Si无取向硅钢冷轧板组织、织构和磁性能的影响。试验结果表明,0.26%~0.81%Al含量时,随钢中Al含量的增加,成品退火钢板的晶粒尺寸增加同时铁损减少;当Al含量大于0.81%时,随Al含量增加,钢板的晶粒尺寸减小,同时铁损增加。Al含量对硅钢板磁感的影响没有明显的规律。2.2%Si无取向硅钢的合适Al含量为0.48%~0.81%。展开更多
文摘The refining effect of Al3Ti1B1RE master alloy on Al sheets used for pressure can manufacture and the behavior of mixed rare earths in master alloy were investigated with XRD, OM, SEM and EDAX. It is found that the refining effect of the refiner on the material has superiority over foreign or domestic Al5Ti1B refiner, and the refiner still retains its refining ability for 6 h after adding it to molten Al, thus improving the strength and plasticity of the material remarkably. The excellent refining effect and stability of AlTiBRE refiner result from that RE can lower the surface energy of molten Al and improve the wetting characteristics of molten Al on refinement nuclei such as TiAl 3, TiB 2, etc., thus giving full play to the effect of heterogeneous nucleation and impeding the congregating tendency of TiB 2 phase in molten Al. At the same time, RE gathering in front of solid/liquid interface are also easy to cause composition supercooling in molten Al, thus impeding the growth of α Al grains and promoting α Al nucleation on refinement nuclei. In addition, RE also play certain role in purification and grain refinement, or modification, especially their effect of purification can improve the metallurgical quality of AlTiBRE master alloy.
基金Supported by Innovation and Technology Fund (No.ITP/045/19AP)Commercial Research&Development (CRD) Funding Supported by Hong Kong Productivity Council (No.10008787)。
文摘We put forward a method of fabricating Aluminum(Al)/carbon fibers(CFs) composite sheets by the accumulative roll bonding(ARB) method. The finished Al/CFs composite sheet has CFs and pure Al sheets as sandwich and surface layers. After cross-section observation of the Al/CFs composite sheet, we found that the CFs discretely distributed within the sandwich layer. Besides, the tensile test showed that the contribution of the sandwich CFs layer to tensile strength was less than 11% compared with annealed pure Al sheet. With ex-situ observation of the CFs breakage evolution with-16%,-32%, and-45% rolling reduction during the ARB process, the plastic instability of the Al layer was found to bring shear damages to the CFs. At last, the bridging strengthening mechanism introduced by CFs was sacrificed. We provide new insight into and instruction on Al/CFs composite sheet preparation method and processing parameters.
基金supported by the Fujian Provincial Natural Science Foundation(No.E0210011)the Educational Commission of Fujian province(No.K20014).
文摘The behavior of flow stress of Al sheets used for pressure can prepared by different melt-treatment during plastic deformation at elevated temperature was studied by isothermal compression test using Gleeble1500 dynamic hot-simulation testing machine. The results show that the AI sheets possess the remarkable characteristic of steady state flow stress when they are deformed in the temperature range of 350-500℃ at strain rates within the range of 0.01-10.0s^-1. A hyperbolic sine relationship is found to correlate well the flow stress with the strain rate, and an Arrhenius relationship with the temperature, which implies that the process of plastic deformation at elevated temperature for this material is thermally activated. Compared with the AI pieces prepared by no or conventional melt-treatment, hot deformation activation energy of AI sheets prepared by high-efficient melt-treatment is the smallest ( Q= 168.0kJ/mol), which reveals that the hot working formability of this material is very better, and has directly to do with the effective improvement of its metallurgical quality.
基金This work was supported by the National Natural Science FoundationShanghai Bao Steel Group of China under Grant No.50374028Doctor Foundation.
文摘The effects of an electric field on AIN precipitation and recrystallization texture were investigated. Cold-rolled 08Al killed steel sheets were annealed at 550℃ according to the two-step processes, for various maintaining times, with and without applying an electric field. It was found that the electric field promotes the precipitation of the second phase (AlN particles), strengthens the γ-fiber and weakens the α-fiber texture component in the recrystallized specimens. A possible explanation for the reinforcement of γ-fiber texture by the electric field is that the second phase AIN particle promotes the growth of γ-fiber at the expense of differently oriented grains.
基金supported by a grant-in-aid of Regional Innovation Center(RIC),New Technology Development and Research Center of Laser Application in Chosun University,Korea.
文摘The object of this work is to investigate the influence of process parameters on drilling characteristics of an Al 1050 sheet with a thickness of 0.2 mm using a pulsed Nd:YAG laser through numerical analyses and experiments. By comparing the numerical analyses with the experiments, a proper numerical model was obtained. From the results of the numerical analyses and the experiments, the effects of process parameters on entrance diameters of drilled holes, shapes of the holes, taper angles of the holes and temperature distributions in the vicinity of the holes were examined quantitatively. In addition, the optimal drilling condition was estimated to improve the quality of the drilled holes.
文摘Al coated steel sheets with excellent heat resistance,thermal reflection,and corrosion resistance are widely used in various applications.The laser weldability of the Al coated steel sheet for full penetration welding was reported.The phenomenon caused by intermixed aluminum and behavior of aluminum in the weld were investigated.Al coated steel sheets that have various thickness and coating mass were prepared for laser welding.The effects of parameters such as welding conditions and Al coating conditions were investigated.Al content mixed in the weld after laser welding was evaluated,and then a correlation between the mixed Al and mechanical properties was investigated.The results show that the Al-rich zones which have Fe-Al intermetallic compounds are found in the weld.The intermetallic compounds cause the decreased strength of the weld.
基金Project(2002AA331050) supported by Hi tech Research and Development Program of China Project(0208) supportedby Science and Technology of Ministry of Education of China
文摘The effects of variation of Mg content on microstructures, the tensile properties and the formability of Al-Mg-Si-Cu alloys for automotive body sheets were investigated by means of scan electron microscopy, optical metallographic analysis, tensile and Ericsson tests. The results show that for Al-Mg-Si-Cu aluminium alloys with excessive Si, with an increment of Mg content, the strength enhances, the specific elongation and Erisson values of alloys decrease, and the number of Mg2Si constituent increases and that of Al(MnFe)Si type constituents reduces. Al-Mg-Si-Cu aluminium alloys with excessive Si for automotive body sheets can present obviously the paint bake hardenability during the paint bake cycle (i.e. artificial aging at 170 ℃ for 30 min immediately after the solution treatment and quenching). Suitable Mg content should be controlled in the range of 0.8% and 1.2%(mass fraction).
基金supported by the National Natural Science Foundation of China (No. 51505323)the Applied Basic Research Program of Shanxi Province,China (Nos. 20210302123117, 20210302124658)。
基金Project(NCET2004) supported by the Program for New Century Excellent Talents in University, China
文摘Ti-Al thin sheet with dimension of 450 mm×450 mm×0.2 mm was prepared by electron beam physical vapor deposition(EB-PVD) technology. The surface and cross-section pattern of as-deposited sample were studied by SEM and AFM,and then the composition and phase were analysed by XRD and EPMA. Finally,the effect on deposit by re-evaporation of Al was explored by calculating the ratio of re-evaporating capacity with depositing capacity of Al on the substrate. The results indicate that the evaporation process with Nb addition into the molten pool makes it earlier to reach the steady-state. The existing equiaxed crystal and columnar crystal along the cross-sectional may be caused by the transformation latent heat released during the transition course of atoms from gaseous state to solid state. The effect on deposit by re-evaporation of Al can be neglected because the re-evaporating capacity of Al is far below that of the depositing capacity.
文摘In this paper, the orientation of grains which adjacent to a developed opening crack was investigated by EBSD. A definition of θ has been came up with which represents the angle between the principal stress plane and each plane of the grains. Smaller θ means easier to crack. It gave a good explanation of the crack propagation throughout the grains. It also revealed that propagation path is along with the plane. This finding will give a prediction of tear properties and help us understanding the cracking mechanism and the behavior of tearing.
基金Project (0321001100) supported by the Henan Province Elitist Innovation Foundation, China
文摘The effects of Sr element on the forming properties of the Al-Mg-Si based alloy sheets were studied by tensile test, metallograph, DSC, XRD, SEM and TEM. The results show that the tensile strength of aluminum alloy sheet added 0.033%(mass fraction)Sr increases comparing with that of free Sr. Simultaneously, the forming properties of sheets evidently increase, the elongation hardenability (n) and plastic strain ratio (r) and Erichsen number increase 27.8%, 11.1%, 10.8% and 12%, respectively, and the forming limit diagram increases evidently, too. The analysis shows that Sr is surface active element, which can refine grains of alloys, promote precipitation, reduce activation energy ofβ' phase, and lead the formation ofα-(Al8Fe2Si) phase instead ofβ-(Al5FeSi) phase. As a result, the forming properties of the alloy sheet increase.
文摘通过拉伸和埃里克森实验以及扫描电镜/能谱、透射电镜和金相分析,研究Mn的质量分数对Al Mg Si Cu铝合金汽车板显微组织、力学性能和成形性的影响·研究表明,随Mn质量分数增加,Al Mg Si Cu汽车板铝合金不可溶结晶相及弥散相粒子数量均增加,不可溶结晶相使合金组织纤维化对板材冲压成形性不利,弥散相粒子阻碍再结晶晶粒长大;提高Mn的质量分数,Al Mg Si Cu汽车板铝合金的强度增加,但延伸率和冲压成形性降低·
文摘通过实验室25 kg真空感应炉冶炼和锻轧研究了0.26%~0.95%Al含量对0.5 mm 2.2%Si无取向硅钢冷轧板组织、织构和磁性能的影响。试验结果表明,0.26%~0.81%Al含量时,随钢中Al含量的增加,成品退火钢板的晶粒尺寸增加同时铁损减少;当Al含量大于0.81%时,随Al含量增加,钢板的晶粒尺寸减小,同时铁损增加。Al含量对硅钢板磁感的影响没有明显的规律。2.2%Si无取向硅钢的合适Al含量为0.48%~0.81%。