The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batte...The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batteries.However,its poor cycling,owing to highpressure phase transitions,is one of its disadvantages.In this study,Cu/Ti was introduced into NFM111 cathode material using a solidphase method.Through both theoretically and experimentally,this study found that Cu doping provides a higher redox potential in NFM111,improving its reversible capacity and charge compensation process.The introduction of Ti would enhance the cycling stability of the material,smooth its charge and discharge curves,and suppress its high-voltage phase transitions.Accordingly,the NaNi_(0.27)Fe_(0.28)Mn_(0.33)Cu_(0.05)Ti_(0.06)O_(2)sample used in the study exhibited a remarkable rate performance of 142.97 mAh·g^(-1)at 0.1 C(2.0-4.2 V)and an excellent capacity retention of 72.81%after 300 cycles at 1C(1C=150 mA·g^(-1)).展开更多
The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up...The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up at the interface and then the plastic deformation of the Ag matrix occurs due to the nucleation and emission of dislocations from the interface and the dislocation propagation through the interface. In addition, it is found that the incipient plastic deformation of Cu/Ag multilayers is postponed, compared with that of bulk single-crystal Cu. The plastic deformation of Cu/Ag multilayers is affected by the lattice mismatch more than by the difference in stacking fault energy （SFE） between Cu and Ag. The dislocation pile-up at the interface is determined by the obstruction of the mismatch dislocation network and the attraction of the image force. Furthermore, this work provides a basis for further understanding and tailoring metal multilayers with good mechanical properties, which may facilitate the design and development of multilayer materials with low cost production strategies.展开更多
GMR effect of multilayers of bcc-Fe(M)(M=Co, Ni) alloy and Cu layers has been investigated. The maximum MR ratio is found at 1.1 nm Fe(Co) and 1.3～1.4 nm Cu layer thickness in [Fe(Co)/CuJ, and at 1.6 nm Fe(Ni) and 1....GMR effect of multilayers of bcc-Fe(M)(M=Co, Ni) alloy and Cu layers has been investigated. The maximum MR ratio is found at 1.1 nm Fe(Co) and 1.3～1.4 nm Cu layer thickness in [Fe(Co)/CuJ, and at 1.6 nm Fe(Ni) and 1.4 nm Cu layer thickness in [Fe(Ni)/Cu]. Under the optimum annealing condition, the MR ratio increases up to 50% and 38% for Fe(Co) and Fe(Ni) systems, respectively. The origin of the increase of GMR is discussed, taking the progress of preferred orientation of Fe(Co)[100] or Fe(Ni)[100] by anneahng into account.展开更多
The magnetic properties of Ni/Cu multilayers, prepared by the electron beam evaporation method under ultra high vacuum conditions, have been systematically studied by magnetic measurements. The temperature dependence ...The magnetic properties of Ni/Cu multilayers, prepared by the electron beam evaporation method under ultra high vacuum conditions, have been systematically studied by magnetic measurements. The temperature dependence of the spontaneous magnetization M (T) is well described by a T3/2 law. A spin wave theory has been used to explain the magnetization versus temperature. Based on this theory, the approximate values for the exchange interactions have been obtained.展开更多
Cu-Al/Al nanostructured metallic multilayers with Al layer thickness hAl varying from 5 to 100 nm were prepared, and their mechanical properties and deformation behaviors were studied by nanoindentation testing. The r...Cu-Al/Al nanostructured metallic multilayers with Al layer thickness hAl varying from 5 to 100 nm were prepared, and their mechanical properties and deformation behaviors were studied by nanoindentation testing. The results showed that the hardness increased drastically with decreasing hAl down to about 20 nm, whereafter the hardness reached a plateau that approaches the hardness of the alloyed Cu-Al monolithic thin films. The strain rate sensitivity （SRS, m）, however, decreased monotonically with reducing hAl. The layer thickness-dependent strengthening mechanisms were discussed, and it was revealed that the alloyed Cu-Al nanolayers dominated at hAl≤ 20 nm, while the crystalline Al nanolayers dominated at hAl 〉 20 nm. The plastic deformation was mainly related to the ductile Al nanolayers, which was responsible for the monotonic evolution of SRS with hAl. In addition, the hAFdependent hardness and SRS were quanti- tatively modeled in light of the strengthening mechanisms at different length scales.展开更多
Al-Cu-Mn-Mg合金因其优异的综合性能,被广泛应用于航空航天和轨道交通等领域。然而,该合金在铸造过程中容易出现热裂缺陷,严重影响铸件的质量和可靠性。因此,提高合金的晶粒细化效果,对于改善合金的铸造性能具有重要意义。Al-Ti-B细化...Al-Cu-Mn-Mg合金因其优异的综合性能,被广泛应用于航空航天和轨道交通等领域。然而,该合金在铸造过程中容易出现热裂缺陷,严重影响铸件的质量和可靠性。因此,提高合金的晶粒细化效果,对于改善合金的铸造性能具有重要意义。Al-Ti-B细化剂是铝合金铸造中最常用的晶粒细化剂,但不同Ti/B质量比的Al-Ti-B细化剂对晶粒细化效果及热裂机制尚未系统研究。采用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电镜(SEM)和CRC(constrained rod cast)金属型约束热裂棒模具等,分析了不同Ti/B质量比的Al-Ti-B细化剂对铸造Al-Cu-Mn-Mg合金微观组织和热裂倾向性的影响。实验结果表明,4种Ti/B比的Al-Ti-B细化剂中Al_3Ti和TiB_2相的含量存在显著差异。在B含量均为0.3%(质量分数)的条件下,添加Al-3Ti-1B、Al-4Ti-1B、Al-5Ti-1B和Al-5Ti-2B的Al-5Cu-0.7Mn-0.55Mg合金的平均晶粒尺寸分别为162.07、113.73、107.81和88.00μm,对应的热裂纹倾向性指数依次为112、136、96和24。微观机制分析表明,Ti B_(2)相的含量对晶粒细化效果和热裂倾向性具有显著影响。特别是Al-5Ti-2B细化剂,在晶粒细化的同时,显著降低了合金的热裂倾向性,展现出优异的性能。展开更多
Based on the microstructure characterization,electrochemical impedance spectroscopy,potentiodynamic polarization,and immersion corrosion,this work comparatively analyzed the differences in the electrochemical corrosio...Based on the microstructure characterization,electrochemical impedance spectroscopy,potentiodynamic polarization,and immersion corrosion,this work comparatively analyzed the differences in the electrochemical corrosion morphology and post-foil formation surface morphology of laser beam welded(LBW)sample and spin-formed sample,and compared the corrosion resistance and Cu foil formation ability of two samples in H_(2)SO_(4)/NaCl solution and CuSO_(4) reducing electrolyte.Results show that in H_(2)SO_(4) and NaCl solutions,LBW sample and spin-formed sample exhibit excellent passivation ability and corrosion resistance.Both samples show uniform corrosion morphologies and similar corrosion resistance in the strong acidic solution containing Cl^(-).Meanwhile,the Cu foil formation ability of the welded joint is similar to that of the spin-formed sample,and both samples obtain intact Cu foils with high-quality surfaces and small differences in properties.展开更多
基金supported by the Low-Cost Long-Life Batteries program,China(No.WL-24-08-01)the National Natural Science Foundation of China(No.22279007)。
文摘The outstanding performance of O3-type NaNi_(1/3)Fe_(1/3)Mn_(1/3)O_(2)(NFM111)at both high and low temperatures coupled with its impressive specific capacity makes it an excellent cathode material for sodium-ion batteries.However,its poor cycling,owing to highpressure phase transitions,is one of its disadvantages.In this study,Cu/Ti was introduced into NFM111 cathode material using a solidphase method.Through both theoretically and experimentally,this study found that Cu doping provides a higher redox potential in NFM111,improving its reversible capacity and charge compensation process.The introduction of Ti would enhance the cycling stability of the material,smooth its charge and discharge curves,and suppress its high-voltage phase transitions.Accordingly,the NaNi_(0.27)Fe_(0.28)Mn_(0.33)Cu_(0.05)Ti_(0.06)O_(2)sample used in the study exhibited a remarkable rate performance of 142.97 mAh·g^(-1)at 0.1 C(2.0-4.2 V)and an excellent capacity retention of 72.81%after 300 cycles at 1C(1C=150 mA·g^(-1)).
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11572118 and 11372103)the Hunan Provincial Science Fund for Distinguished Young Scholars,China(Grant No.2015JJ1006)the National Key Research and Development Program of China(Grant No.2016YFB0700300)
文摘The plastic deformation mechanism of Cu/Ag multilayers is investigated by molecular dynamics （MD） simulation in a nanoindentation process. The result shows that due to the interface barrier, the dislocations pile-up at the interface and then the plastic deformation of the Ag matrix occurs due to the nucleation and emission of dislocations from the interface and the dislocation propagation through the interface. In addition, it is found that the incipient plastic deformation of Cu/Ag multilayers is postponed, compared with that of bulk single-crystal Cu. The plastic deformation of Cu/Ag multilayers is affected by the lattice mismatch more than by the difference in stacking fault energy （SFE） between Cu and Ag. The dislocation pile-up at the interface is determined by the obstruction of the mismatch dislocation network and the attraction of the image force. Furthermore, this work provides a basis for further understanding and tailoring metal multilayers with good mechanical properties, which may facilitate the design and development of multilayer materials with low cost production strategies.
基金Ministry of Education, Science, Sports and Culture under Grantin-Aid for Scielltific Research on Priority Areas (A), Japan!(No.
文摘GMR effect of multilayers of bcc-Fe(M)(M=Co, Ni) alloy and Cu layers has been investigated. The maximum MR ratio is found at 1.1 nm Fe(Co) and 1.3～1.4 nm Cu layer thickness in [Fe(Co)/CuJ, and at 1.6 nm Fe(Ni) and 1.4 nm Cu layer thickness in [Fe(Ni)/Cu]. Under the optimum annealing condition, the MR ratio increases up to 50% and 38% for Fe(Co) and Fe(Ni) systems, respectively. The origin of the increase of GMR is discussed, taking the progress of preferred orientation of Fe(Co)[100] or Fe(Ni)[100] by anneahng into account.
文摘The magnetic properties of Ni/Cu multilayers, prepared by the electron beam evaporation method under ultra high vacuum conditions, have been systematically studied by magnetic measurements. The temperature dependence of the spontaneous magnetization M (T) is well described by a T3/2 law. A spin wave theory has been used to explain the magnetization versus temperature. Based on this theory, the approximate values for the exchange interactions have been obtained.
基金supported by the National Natural Science Foundation of China(Grant Nos.5132100351322104and 51201123)+5 种基金the National Basic Research Program of China(Grant No.2010CB631003)the 111 Project of China(Grant No.B06025)the support from the Fundamental Research Funds for the Central Universitiesthe Tengfei Scholar projectthe Natural Science Basic Research Plan in Shaanxi Province of China(Program No.2015JM5158)the Shaanxi Province Postdoctoral Scientific Research Project for partial financial support
文摘Cu-Al/Al nanostructured metallic multilayers with Al layer thickness hAl varying from 5 to 100 nm were prepared, and their mechanical properties and deformation behaviors were studied by nanoindentation testing. The results showed that the hardness increased drastically with decreasing hAl down to about 20 nm, whereafter the hardness reached a plateau that approaches the hardness of the alloyed Cu-Al monolithic thin films. The strain rate sensitivity （SRS, m）, however, decreased monotonically with reducing hAl. The layer thickness-dependent strengthening mechanisms were discussed, and it was revealed that the alloyed Cu-Al nanolayers dominated at hAl≤ 20 nm, while the crystalline Al nanolayers dominated at hAl 〉 20 nm. The plastic deformation was mainly related to the ductile Al nanolayers, which was responsible for the monotonic evolution of SRS with hAl. In addition, the hAFdependent hardness and SRS were quanti- tatively modeled in light of the strengthening mechanisms at different length scales.
文摘Al-Cu-Mn-Mg合金因其优异的综合性能,被广泛应用于航空航天和轨道交通等领域。然而,该合金在铸造过程中容易出现热裂缺陷,严重影响铸件的质量和可靠性。因此,提高合金的晶粒细化效果,对于改善合金的铸造性能具有重要意义。Al-Ti-B细化剂是铝合金铸造中最常用的晶粒细化剂,但不同Ti/B质量比的Al-Ti-B细化剂对晶粒细化效果及热裂机制尚未系统研究。采用X射线衍射仪(XRD)、光学显微镜(OM)、扫描电镜(SEM)和CRC(constrained rod cast)金属型约束热裂棒模具等,分析了不同Ti/B质量比的Al-Ti-B细化剂对铸造Al-Cu-Mn-Mg合金微观组织和热裂倾向性的影响。实验结果表明,4种Ti/B比的Al-Ti-B细化剂中Al_3Ti和TiB_2相的含量存在显著差异。在B含量均为0.3%(质量分数)的条件下,添加Al-3Ti-1B、Al-4Ti-1B、Al-5Ti-1B和Al-5Ti-2B的Al-5Cu-0.7Mn-0.55Mg合金的平均晶粒尺寸分别为162.07、113.73、107.81和88.00μm,对应的热裂纹倾向性指数依次为112、136、96和24。微观机制分析表明,Ti B_(2)相的含量对晶粒细化效果和热裂倾向性具有显著影响。特别是Al-5Ti-2B细化剂,在晶粒细化的同时,显著降低了合金的热裂倾向性,展现出优异的性能。
基金Key Research and Development Program of Shaanxi Province(2022GY-410)Funding of Western Titanium Technologies Co.,Ltd(WX2210)。
文摘Based on the microstructure characterization,electrochemical impedance spectroscopy,potentiodynamic polarization,and immersion corrosion,this work comparatively analyzed the differences in the electrochemical corrosion morphology and post-foil formation surface morphology of laser beam welded(LBW)sample and spin-formed sample,and compared the corrosion resistance and Cu foil formation ability of two samples in H_(2)SO_(4)/NaCl solution and CuSO_(4) reducing electrolyte.Results show that in H_(2)SO_(4) and NaCl solutions,LBW sample and spin-formed sample exhibit excellent passivation ability and corrosion resistance.Both samples show uniform corrosion morphologies and similar corrosion resistance in the strong acidic solution containing Cl^(-).Meanwhile,the Cu foil formation ability of the welded joint is similar to that of the spin-formed sample,and both samples obtain intact Cu foils with high-quality surfaces and small differences in properties.
