The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology.Here we report a systematical study on the microstructures,magnetic properties...The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology.Here we report a systematical study on the microstructures,magnetic properties and cryogenic magneto-caloric performances of the Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons.It is found that the ribbons reveal a second-order phase transition and are accompanied by a table-shaped magneto-caloric effect.The calculated magneticentropy-change maximum |ΔSM|,temperature averaged entropy change(i.e.,TEC(10)),and refrigerant capacity reach 13.9 J/kg·K,13.84 J/kg-K and 740 J/kg with magnetic field change of 0-7 T,respectively,indicating that the present Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons are good candidates for magnetic cooling.展开更多
The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morpholo...The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morphology on the fracture surfaces. Approaching the ribbon boundary, these damage cavities assemble and form the nanoscale periodic corrugations, which are neither Wallner lines nor crack front waves. The periodic corrugations result from the interactions between the reflected elastic waves by the boundaries of amorphous ribbon and the stress fields of the crack tip.展开更多
We investigated the variation of permeability spectra and relaxation frequency in Co-based amorphous ribbon annealed by pulsed Nd:YAG laser at various annealing energy Ea. The complex permeability spectra varies sensi...We investigated the variation of permeability spectra and relaxation frequency in Co-based amorphous ribbon annealed by pulsed Nd:YAG laser at various annealing energy Ea. The complex permeability spectra varies sensitively with the annealing energy, where the spectra could be decomposed into two contributions from domain wall motion,μdw(f) and rotational magnetization μrot(f) by analyzing the measured spectra as a function of driving ac field amplitude. The magnitude of μdw(f) and μrot(f) in dc limit shows maximum at Ea = 176 mJ. The maximum relaxation frequency for rotational magnetization, determined by μ'(f) curve, is about 700 kHz at Ea=62 mJ but that for wall motion is about 26 kHz at 230 mJ. These variations reflect the increase of magnetic softness and microstructural change by the annealing.展开更多
The giant stress-impedance (GSI) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 ribbons has been investigated. The results showed that the GSI effect changed drastically with annealing techniques and th...The giant stress-impedance (GSI) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 ribbons has been investigated. The results showed that the GSI effect changed drastically with annealing techniques and the maximum stress impedance ratio of 350% was obtained after optimal conditions of current annealing. The behaviors of the stress impedance vary with densities of annealing current and the stress longitudinally applied during current annealing. The maximum change of stress impedance existed in the sample annealed by high-current-density electropulsing under applied stress of 100 MPa.展开更多
The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380℃ in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electro...The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380℃ in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron micros- copy (SEM). The mechanism of oxides formation of the amorphous ribbons was discussed in detail. The results showed that the oxides were mostly B2O3 , SiO2 and Fe2O3 or FeO. With the increase of annealing time and holding temperature, the fraction of the oxides on the ribbon surface increased and the size of the oxides became larger due to the generation of new oxides and the coalescence of small oxides. The oxides have different shapes, such as round, rod and needle-shaped. Experimental results also showed that the oxides nucleated at fish scale, air pocket and impu-rities in priority, and the growth of the oxides was controlled by the diffusion of atoms. With the increase of the distance to the ribbon surface, the oxygen concentration decreased dramatically. Due to the low binding energy of B2O3 and the large diffusion coefficient of B atom, the B elemaent was oxidized firstly compared with other elements. More- over, the oxidation deoths of the B2O3 and SiO2 were larger than that of Fe2O3.展开更多
Ms-T curves and hysteresis loops were investigated for amorphous Fe78Si9B13, (FeNi)78(CrSiB)22, their lap-wound-cores, and their composite ribbons made by two-chamber-crucible technique. The properties of the lap-woun...Ms-T curves and hysteresis loops were investigated for amorphous Fe78Si9B13, (FeNi)78(CrSiB)22, their lap-wound-cores, and their composite ribbons made by two-chamber-crucible technique. The properties of the lap-wound cores of the two kinds of ribbons are similar. For the composite ribbons, the intrinsic properties are the average of the two alloys. Their technological properties, i.e., hysteresis loops, however, are no longer the average of the two alloys. Instead, they show some dramatic changes compared to the lap-wound-cores. Especially, the shape of the hysteresis loop of the composite ribbon cores is largely different from that of lap-wound-cores. The reason for the difference is supposed to be internal stress induced from cooling after annealing.展开更多
Amorphous Ti–Cu–Zr–Ni alloys with minor addition of Sn and Al were prepared by melt spinning technique.The effects of Sn and Al additions on the microstructures and mechanical properties of glassy ribbons were inve...Amorphous Ti–Cu–Zr–Ni alloys with minor addition of Sn and Al were prepared by melt spinning technique.The effects of Sn and Al additions on the microstructures and mechanical properties of glassy ribbons were investigated.The amorphous state of ribbons was confirmed by x-ray diffraction and transmission electron microscopy,where those ribbons with Sn addition exhibited a fully amorphous state.The characteristic temperature indicates that Ti45Cu35Zr10Ni5Sn5 alloy has a stronger glass-forming ability,as proven by differential scanning calorimetry.Ti45Cu35Zr10Ni5Al5 alloy showed a better hardness of 9.23 GPa and elastic modulus of 127.15 GPa and good wear resistance.Ti45Cu35Zr10Ni5Sn5 alloy displayed a pop-in event related to discrete plasticity according to nanoindentation.When the temperature is below 560 K,Ti45Cu35Zr10Ni5Sn5 alloy mainly exhibits elasticity.When the temperature rises between 717 K and 743 K,it shows a significant increase in elasticity but decrease in viscoelasticity after the ribbon experiences the main relaxation at 717 K.When the temperature is above 743 K,the ribbon shows viscoplasticity.展开更多
基金Project supported by the National Natural Science Foundation of China(Grant No.52071197)the Science and Technology Committee of Shanghai(Grant No.19ZR1418300)+2 种基金the Independent Research and Development Project of State Key Laboratory of Advanced Special SteelShanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai University(Grant No.SKLASS 2019-Z003)the Science and Technology Commission of Shanghai Municipality(Grant No.19DZ2270200)。
文摘The magnetic cooling utilizing magneto-caloric effect is recognized as promising energy efficiency and environmentally friendly technology.Here we report a systematical study on the microstructures,magnetic properties and cryogenic magneto-caloric performances of the Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons.It is found that the ribbons reveal a second-order phase transition and are accompanied by a table-shaped magneto-caloric effect.The calculated magneticentropy-change maximum |ΔSM|,temperature averaged entropy change(i.e.,TEC(10)),and refrigerant capacity reach 13.9 J/kg·K,13.84 J/kg-K and 740 J/kg with magnetic field change of 0-7 T,respectively,indicating that the present Gd_(20)Ho_(20)Tm_(20)Cu_(20)Ni_(20) amorphous ribbons are good candidates for magnetic cooling.
文摘The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morphology on the fracture surfaces. Approaching the ribbon boundary, these damage cavities assemble and form the nanoscale periodic corrugations, which are neither Wallner lines nor crack front waves. The periodic corrugations result from the interactions between the reflected elastic waves by the boundaries of amorphous ribbon and the stress fields of the crack tip.
文摘We investigated the variation of permeability spectra and relaxation frequency in Co-based amorphous ribbon annealed by pulsed Nd:YAG laser at various annealing energy Ea. The complex permeability spectra varies sensitively with the annealing energy, where the spectra could be decomposed into two contributions from domain wall motion,μdw(f) and rotational magnetization μrot(f) by analyzing the measured spectra as a function of driving ac field amplitude. The magnitude of μdw(f) and μrot(f) in dc limit shows maximum at Ea = 176 mJ. The maximum relaxation frequency for rotational magnetization, determined by μ'(f) curve, is about 700 kHz at Ea=62 mJ but that for wall motion is about 26 kHz at 230 mJ. These variations reflect the increase of magnetic softness and microstructural change by the annealing.
基金This work was supported by the National Natural ScienceFoundation of China (Grant No.5017106).
文摘The giant stress-impedance (GSI) effect in amorphous and current annealed Fe73.5Cu1Nb3Si13.5B9 ribbons has been investigated. The results showed that the GSI effect changed drastically with annealing techniques and the maximum stress impedance ratio of 350% was obtained after optimal conditions of current annealing. The behaviors of the stress impedance vary with densities of annealing current and the stress longitudinally applied during current annealing. The maximum change of stress impedance existed in the sample annealed by high-current-density electropulsing under applied stress of 100 MPa.
基金Item Sponsored by National Natural Science Foundation of China(51374080)
文摘The oxidation behavior of Fe-based amorphous ribbons was tested by annealing at 380℃ in air for different time with heat treatment furnace and analyzed by X-ray photoelectron spectroscopy (XPS) and scanning electron micros- copy (SEM). The mechanism of oxides formation of the amorphous ribbons was discussed in detail. The results showed that the oxides were mostly B2O3 , SiO2 and Fe2O3 or FeO. With the increase of annealing time and holding temperature, the fraction of the oxides on the ribbon surface increased and the size of the oxides became larger due to the generation of new oxides and the coalescence of small oxides. The oxides have different shapes, such as round, rod and needle-shaped. Experimental results also showed that the oxides nucleated at fish scale, air pocket and impu-rities in priority, and the growth of the oxides was controlled by the diffusion of atoms. With the increase of the distance to the ribbon surface, the oxygen concentration decreased dramatically. Due to the low binding energy of B2O3 and the large diffusion coefficient of B atom, the B elemaent was oxidized firstly compared with other elements. More- over, the oxidation deoths of the B2O3 and SiO2 were larger than that of Fe2O3.
文摘Ms-T curves and hysteresis loops were investigated for amorphous Fe78Si9B13, (FeNi)78(CrSiB)22, their lap-wound-cores, and their composite ribbons made by two-chamber-crucible technique. The properties of the lap-wound cores of the two kinds of ribbons are similar. For the composite ribbons, the intrinsic properties are the average of the two alloys. Their technological properties, i.e., hysteresis loops, however, are no longer the average of the two alloys. Instead, they show some dramatic changes compared to the lap-wound-cores. Especially, the shape of the hysteresis loop of the composite ribbon cores is largely different from that of lap-wound-cores. The reason for the difference is supposed to be internal stress induced from cooling after annealing.
基金National Natural Science Foundation of China(Grant Nos.51671161,U1806219,U1660108,and 51327901)the Research Project of the Natural Science Foundation of Shanxi Province,China(Grant Nos.2017JM5116 and 2020JZ-08).
文摘Amorphous Ti–Cu–Zr–Ni alloys with minor addition of Sn and Al were prepared by melt spinning technique.The effects of Sn and Al additions on the microstructures and mechanical properties of glassy ribbons were investigated.The amorphous state of ribbons was confirmed by x-ray diffraction and transmission electron microscopy,where those ribbons with Sn addition exhibited a fully amorphous state.The characteristic temperature indicates that Ti45Cu35Zr10Ni5Sn5 alloy has a stronger glass-forming ability,as proven by differential scanning calorimetry.Ti45Cu35Zr10Ni5Al5 alloy showed a better hardness of 9.23 GPa and elastic modulus of 127.15 GPa and good wear resistance.Ti45Cu35Zr10Ni5Sn5 alloy displayed a pop-in event related to discrete plasticity according to nanoindentation.When the temperature is below 560 K,Ti45Cu35Zr10Ni5Sn5 alloy mainly exhibits elasticity.When the temperature rises between 717 K and 743 K,it shows a significant increase in elasticity but decrease in viscoelasticity after the ribbon experiences the main relaxation at 717 K.When the temperature is above 743 K,the ribbon shows viscoplasticity.