Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic propertie...Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic properties of the ribbons was investigated. Both the free and wheel side of the ribbons could obtain strong c-axis crystal texture of Nd2Fe14B phase perpendicular to the ribbons surface at low wheel speed,but the texture weakened gradually with the increase of the wheel speed. Increase of Nd content led to better formation of crystal texture in the ribbons,indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic measurement results showed that the magnetic anisotropy of the ribbons exhibited corresponding behavior with the invariance of the c-axis crystal texture of Nd2Fe14B phase in the ribbons,and the coercivity of the ribbons rose with the increase of both Nd content and wheel speed during melt-spun process.展开更多
Ⅰ. INTRODUCTION In the past experiments on the magnetic quenching of positronium atom （a hydrogenlike bound state of positron and dectron ）, the plastic scintillator and BaF<sub>2</sub> crystal were usu...Ⅰ. INTRODUCTION In the past experiments on the magnetic quenching of positronium atom （a hydrogenlike bound state of positron and dectron ）, the plastic scintillator and BaF<sub>2</sub> crystal were usually used as the detectors in the positron lifetime spectrometer. In those cases, a long light guide between the detector and the photomultiplier was exclusively necessary for keeping展开更多
The theory of magnetic quenching of positron annihilation is introduced in this paper.The positron annihilation technique is widely used in the studies of irradiation induced voids in various materials.The positronium...The theory of magnetic quenching of positron annihilation is introduced in this paper.The positron annihilation technique is widely used in the studies of irradiation induced voids in various materials.The positronium formation rate can change in a magnetic fields in order to study the magnetic quenching.展开更多
Based on a transient temperature distribution of a 45 steel cylinder workpiece during magnetic quenching, which was obtainedby solving the governing equations with nonlinear boundary on the condition of coupling effec...Based on a transient temperature distribution of a 45 steel cylinder workpiece during magnetic quenching, which was obtainedby solving the governing equations with nonlinear boundary on the condition of coupling effects of heat-magnetism. Accordingto the theory of thermal non-elasticity, computational mechanics, ferromagnetism and phase transformation, a new constitutiveequation considering effects of phase transformation is proposed and solved by means of finite element method. The transientthermal stress and residual stress are obtained and the influencing factors on the thermal stress of magnetic field are analyzedand discussed.展开更多
A series of materials of composition Fe87Zr7B6,Fe87Zr7B5Ag1,Fe87Zr7B5Cu1 have been prepared by the melt spinning method for different cooling speed to get completely or partly amorphous ribbons.It is proved that the c...A series of materials of composition Fe87Zr7B6,Fe87Zr7B5Ag1,Fe87Zr7B5Cu1 have been prepared by the melt spinning method for different cooling speed to get completely or partly amorphous ribbons.It is proved that the crystallization process is composed of 2 steps.The first step is the precipitation of&-Fe only and the second step is the phase separation of&-Fe,Fe2Zr and Fe2B.All our own made materials have been used in the library monitoring system.Most of them showed a capability of triggling the alarm of the system.The triggling sensitivity at different positions and different sample geometry were investigated and the physical mechanisms were analyzed.展开更多
基金Project supported by the National Natural Science Foundation of China (50871003, 20971116)the Key Project of the International Coopera-tion and Exchanges of Zhejiang Province (2006C14014)
文摘Crystallographic alignment and magnetic anisotropy were studied for NdxFe94–xB6 （x=8,9,10,11） ribbons prepared via melt-spinning. Effect of Nd content and wheel speed on the crystal structure and magnetic properties of the ribbons was investigated. Both the free and wheel side of the ribbons could obtain strong c-axis crystal texture of Nd2Fe14B phase perpendicular to the ribbons surface at low wheel speed,but the texture weakened gradually with the increase of the wheel speed. Increase of Nd content led to better formation of crystal texture in the ribbons,indicating that the α-Fe phase might undermine the formation of crystal texture. Magnetic measurement results showed that the magnetic anisotropy of the ribbons exhibited corresponding behavior with the invariance of the c-axis crystal texture of Nd2Fe14B phase in the ribbons,and the coercivity of the ribbons rose with the increase of both Nd content and wheel speed during melt-spun process.
基金Project supported by the National Natural Science Foundation of China.
文摘Ⅰ. INTRODUCTION In the past experiments on the magnetic quenching of positronium atom （a hydrogenlike bound state of positron and dectron ）, the plastic scintillator and BaF<sub>2</sub> crystal were usually used as the detectors in the positron lifetime spectrometer. In those cases, a long light guide between the detector and the photomultiplier was exclusively necessary for keeping
文摘The theory of magnetic quenching of positron annihilation is introduced in this paper.The positron annihilation technique is widely used in the studies of irradiation induced voids in various materials.The positronium formation rate can change in a magnetic fields in order to study the magnetic quenching.
文摘Based on a transient temperature distribution of a 45 steel cylinder workpiece during magnetic quenching, which was obtainedby solving the governing equations with nonlinear boundary on the condition of coupling effects of heat-magnetism. Accordingto the theory of thermal non-elasticity, computational mechanics, ferromagnetism and phase transformation, a new constitutiveequation considering effects of phase transformation is proposed and solved by means of finite element method. The transientthermal stress and residual stress are obtained and the influencing factors on the thermal stress of magnetic field are analyzedand discussed.
文摘A series of materials of composition Fe87Zr7B6,Fe87Zr7B5Ag1,Fe87Zr7B5Cu1 have been prepared by the melt spinning method for different cooling speed to get completely or partly amorphous ribbons.It is proved that the crystallization process is composed of 2 steps.The first step is the precipitation of&-Fe only and the second step is the phase separation of&-Fe,Fe2Zr and Fe2B.All our own made materials have been used in the library monitoring system.Most of them showed a capability of triggling the alarm of the system.The triggling sensitivity at different positions and different sample geometry were investigated and the physical mechanisms were analyzed.
