The damage characteristics of different speed sections of Cu−Cr−Zr alloy rail after simulated launch were studied.The microstructure,morphologies and properties of samples were investigated by using XRD,XPS,EBSD,SEM,h...The damage characteristics of different speed sections of Cu−Cr−Zr alloy rail after simulated launch were studied.The microstructure,morphologies and properties of samples were investigated by using XRD,XPS,EBSD,SEM,hardness test,electrochemical test and DSC techniques.It was found that deposition layers were formed on the surfaces of the simulated launch samples.The thickness and surface roughness of these deposition layers increased with increasing the heat effect,suggesting a launch speed dependent damage degree of the arc ablation.The hardness variation of samples is attributed to the effects of the deposition layer and deformation hardening.The surface deposition layer affects corrosion resistance and crystalline characteristics,leading to changes in subsequent service performances.Additionally,the surface texture and plastic deformation ability of the samples are related to the recrystallization degree and deformation grain amount.展开更多
CoNiFe,CoNiFeB and CoNiFeP soft magnetic thin films were prepared by cyclic voltammetry method.The morphologies,composition and structures were characterized by scanning electron microscope（SEM）,energy-dispersive X-...CoNiFe,CoNiFeB and CoNiFeP soft magnetic thin films were prepared by cyclic voltammetry method.The morphologies,composition and structures were characterized by scanning electron microscope（SEM）,energy-dispersive X-ray spectroscope（EDS） and X-ray diffractometer（XRD）.The soft magnetic properties were investigated through vibrating sample magnetometer（VSM）.The corrosion resistance was investigated through Tafel polarization and electrochemical impedance spectroscopic（EIS）.The results show that all the electrodeposited CoNiFe,CoNiFeB and CoNiFeP films are mixtures of crystalline and amorphous phases,and high amount of boron/phosphorus-containing additives favors the formation of amorphous state.Nanostructure is obtained in CoNiFe and CoNiFeB films.The inclusion of boron causes the film more dense and also increases its corrosion resistance.Meanwhile,the inclusion of boron lowers its coercivity（Hc） from 851.48 A/m to 604.79 A/m,but the saturation magnetic flux density（Bs） is almost unchanged.However,the addition of phosphorus greatly increases the film particle size and decreases its corrosion stability.The coercivity（Hc） of CoNiFeP film is also highly increased to 12485.79 A/m,and its saturation magnetic flux density（Bs） is greatly decreased to 1.25 T.展开更多
Nanocrystalline NdFeB film was fabricated onto the copper substrate through direct current electroplating method,and characterized by scanning electron microscope(SEM) coupled with energy dispersive X-ray spectroscope...Nanocrystalline NdFeB film was fabricated onto the copper substrate through direct current electroplating method,and characterized by scanning electron microscope(SEM) coupled with energy dispersive X-ray spectroscope(EDS),vibrating sample magnetometer and potentiodynamic polarization techniques.The initial electroplating behavior was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) techniques.Results revealed that the corrosion resistance of the NdFeB film was better than that of the traditional sintered NdFeB magnet.The depositing process of the NdFeB film followed the three-dimensional nucleation and subsequent grain growth mechanism,and was controlled by charger transfer.With the increase of the negative potential bias,the deposition mechanism of NdFeB film changed from heterogeneous to homogeneous nucleation/growth,which consequently resulted in the decrease of charge-transfer-resistance.展开更多
Magnetism and the stability of (Ga 1-xFe x)As are investigated using the first principles LMTO-ASA band calculation by assuming supercell structures.Four concentrations of the 3d impurities are studied (x=1,1/2,1/...Magnetism and the stability of (Ga 1-xFe x)As are investigated using the first principles LMTO-ASA band calculation by assuming supercell structures.Four concentrations of the 3d impurities are studied (x=1,1/2,1/4,and 1/8).The results show the effect of varying Fe concentration on the magnetic and stable properties.展开更多
Electromagnetic forming tests were done at room temperature to reveal the influence of hydrogen content on the compressive properties of Ti-6Al-4V alloy at high strain rate. Microstructure was observed to reveal the m...Electromagnetic forming tests were done at room temperature to reveal the influence of hydrogen content on the compressive properties of Ti-6Al-4V alloy at high strain rate. Microstructure was observed to reveal the mechanism of hydrogen-enhanced compressive properties. The experimental results indicate that hydrogen has favorable effects on the compressive properties of Ti-6Al-4V alloy at high strain rate. Compression of Ti-6Al-4V alloy first increases up to a maximum and then decreases with the increase of hydrogen content at the same discharge energy under EMF tests. The compression increases by 47.0% when 0.2% (mass fraction) hydrogen is introduced into Ti-6Al-4V alloy. The optimal hydrogen content for cold formation of Ti–6Al–4V alloy under EMF was determined. The reasons for the hydrogen-induced compressive properties were discussed.展开更多
基金the Key Research and Development Program of China(No.2022YFB2404102)the National Natural Science Foundation of China(Nos.51971093,52171158,52101196)+5 种基金the Key Research and Development Program of Shandong Province,China(Nos.2020ZLYS11,2021ZLGX01,2022CXGC020308,2023CXGC010308)the Major Innovation Projects of Shandong Province,China(Nos.2020CXGC010701,2020CXGC010702)the Young Taishan Scholars,China(No.tsqn202211184)the Shandong Provincial Natural Science Foundation,China(No.ZR2022ME137)the Yantai Science and Technology Planning Project,China(No.2021ZDCX001)the Open Project Program of Shandong Marine Aerospace Equipment Technological Innovation Center(Ludong University),China(No.MAETIC2021-11).
文摘The damage characteristics of different speed sections of Cu−Cr−Zr alloy rail after simulated launch were studied.The microstructure,morphologies and properties of samples were investigated by using XRD,XPS,EBSD,SEM,hardness test,electrochemical test and DSC techniques.It was found that deposition layers were formed on the surfaces of the simulated launch samples.The thickness and surface roughness of these deposition layers increased with increasing the heat effect,suggesting a launch speed dependent damage degree of the arc ablation.The hardness variation of samples is attributed to the effects of the deposition layer and deformation hardening.The surface deposition layer affects corrosion resistance and crystalline characteristics,leading to changes in subsequent service performances.Additionally,the surface texture and plastic deformation ability of the samples are related to the recrystallization degree and deformation grain amount.
基金Projects(50771092,21073162) supported by the National Natural Science Foundation of ChinaProject(2005DKA10400-Z15) supported by the Ministry of Science and Technology of China
文摘CoNiFe,CoNiFeB and CoNiFeP soft magnetic thin films were prepared by cyclic voltammetry method.The morphologies,composition and structures were characterized by scanning electron microscope（SEM）,energy-dispersive X-ray spectroscope（EDS） and X-ray diffractometer（XRD）.The soft magnetic properties were investigated through vibrating sample magnetometer（VSM）.The corrosion resistance was investigated through Tafel polarization and electrochemical impedance spectroscopic（EIS）.The results show that all the electrodeposited CoNiFe,CoNiFeB and CoNiFeP films are mixtures of crystalline and amorphous phases,and high amount of boron/phosphorus-containing additives favors the formation of amorphous state.Nanostructure is obtained in CoNiFe and CoNiFeB films.The inclusion of boron causes the film more dense and also increases its corrosion resistance.Meanwhile,the inclusion of boron lowers its coercivity（Hc） from 851.48 A/m to 604.79 A/m,but the saturation magnetic flux density（Bs） is almost unchanged.However,the addition of phosphorus greatly increases the film particle size and decreases its corrosion stability.The coercivity（Hc） of CoNiFeP film is also highly increased to 12485.79 A/m,and its saturation magnetic flux density（Bs） is greatly decreased to 1.25 T.
基金Project(2008BS04030)supported by Research Award Fund for Outstanding Young Scientists in Shandong Province,China
文摘Nanocrystalline NdFeB film was fabricated onto the copper substrate through direct current electroplating method,and characterized by scanning electron microscope(SEM) coupled with energy dispersive X-ray spectroscope(EDS),vibrating sample magnetometer and potentiodynamic polarization techniques.The initial electroplating behavior was investigated by cyclic voltammetry(CV) and electrochemical impedance spectroscopy(EIS) techniques.Results revealed that the corrosion resistance of the NdFeB film was better than that of the traditional sintered NdFeB magnet.The depositing process of the NdFeB film followed the three-dimensional nucleation and subsequent grain growth mechanism,and was controlled by charger transfer.With the increase of the negative potential bias,the deposition mechanism of NdFeB film changed from heterogeneous to homogeneous nucleation/growth,which consequently resulted in the decrease of charge-transfer-resistance.
文摘Magnetism and the stability of (Ga 1-xFe x)As are investigated using the first principles LMTO-ASA band calculation by assuming supercell structures.Four concentrations of the 3d impurities are studied (x=1,1/2,1/4,and 1/8).The results show the effect of varying Fe concentration on the magnetic and stable properties.
基金Project (51205102) supported by the National Natural Science Foundation of ChinaProject (2012M511401) supported by the China Postdoctoral Science FoundationProject (gf201101001) supported by the National Defense Key Disciplines Laboratory of Light Alloy Processing Science and Technology, Nanchang Hangkong University, China
文摘Electromagnetic forming tests were done at room temperature to reveal the influence of hydrogen content on the compressive properties of Ti-6Al-4V alloy at high strain rate. Microstructure was observed to reveal the mechanism of hydrogen-enhanced compressive properties. The experimental results indicate that hydrogen has favorable effects on the compressive properties of Ti-6Al-4V alloy at high strain rate. Compression of Ti-6Al-4V alloy first increases up to a maximum and then decreases with the increase of hydrogen content at the same discharge energy under EMF tests. The compression increases by 47.0% when 0.2% (mass fraction) hydrogen is introduced into Ti-6Al-4V alloy. The optimal hydrogen content for cold formation of Ti–6Al–4V alloy under EMF was determined. The reasons for the hydrogen-induced compressive properties were discussed.
