The direct observations of the atomic arrangements in both conventional furnace annealed and electric pulse rapid annealed Fe78B13Si9 amorphous alloy have been conducted by the lattice imaging technique in a higt reso...The direct observations of the atomic arrangements in both conventional furnace annealed and electric pulse rapid annealed Fe78B13Si9 amorphous alloy have been conducted by the lattice imaging technique in a higt resolution electron microscope. The results showed that the embrittlement of the alloy was related to the extent of atomic rearrangements during the annealing processes. The embrittlement of the alloy after 1hour conventional furnace annealing at about 270℃ is caused by the sufficient atomic rearrangements which are characterized by the growth of some bct Fe3B-like atomic short range ordering regions already existed in the as-quenched structure. Electric pulse rapid annealing can effectively retard the above-mentioned atomic rearrangements and thus restrain the embrittlement. The embrittlement only occurs when certain amount of bcc α-Fe nanocrystals are precipitated in the amorphous matrix during electric pulse rapid annealing.展开更多
Ion beam sputtering profiling in combination with SIMS technique was employed to investigate the Al diffusion in Fe_(78)Si_0B_(13)amorphous alloy.Between 320 and 380℃,the diffusion coefficients vary from 2.43×10...Ion beam sputtering profiling in combination with SIMS technique was employed to investigate the Al diffusion in Fe_(78)Si_0B_(13)amorphous alloy.Between 320 and 380℃,the diffusion coefficients vary from 2.43×10^(-22) to 2.01×10^(-21)m^2s^(-1),and an Arrhenius relationship was established as:D_0=2.02×10~_(12)exp(-1.17/kT)展开更多
The thermal expansion along the longitudinal and transverse directions for amorphous Fe_(78)B_(13)Si_9 alloy prepared under various preparing conditions were investigated.The thermal expansion anisotropy appears in al...The thermal expansion along the longitudinal and transverse directions for amorphous Fe_(78)B_(13)Si_9 alloy prepared under various preparing conditions were investigated.The thermal expansion anisotropy appears in all specimens.The expansion along the longitudinal direction is less than that along the transverse direction.The cooling rate,the melt temperature before jet casting and the cycling temperature affect the thermal expansion coefficients and anisotropy.The amisotropy of thermal expansion originates from the orientation of atomic interaction force,the atomic oscillatory frequency and short range order structure or the directional arrangement of defects in the alloy.展开更多
A new method was developed for preparing nanocrystalline alloy made of the identi- cal compositional Fe_(78)B_(13)Si_9 amorphous ribbon by suitable isothermal annealing.Its microstructure and some structure-sensitive ...A new method was developed for preparing nanocrystalline alloy made of the identi- cal compositional Fe_(78)B_(13)Si_9 amorphous ribbon by suitable isothermal annealing.Its microstructure and some structure-sensitive properties.including thermal expansion,spe- cific heat,etc.,have been studied and measured.Comparative analysis of properties was also carried out with amorphous and coarse-grained crystalline alloys of same composi- tion,thus.it is believed that so novel differences in properties from usual materials would be made by the particular microstructure of short range disorder of the nanocrystalline alloy.展开更多
The nanocrystalline structure of annealed Fe73.5 Cu1 W3Si13.5B9 alloy has been investigated by using the XRD and the TEM methods. The relation between the initial permeability and the microstructure of the annealed al...The nanocrystalline structure of annealed Fe73.5 Cu1 W3Si13.5B9 alloy has been investigated by using the XRD and the TEM methods. The relation between the initial permeability and the microstructure of the annealed alloy has been discussed. The crystalline phase in annealed Fe73.5 Cu1 W3Si13.5B9 alloy is the α-Fe(Si) phase with DO3 superstructure. The volume fraction, Si content and degree of order of the αFe(Si) phase increase with increasing annealing temperature. In the temperature range of 490-570℃, the α-Fe(Si) phase has a size of 13 nm, and its grain number increases as the annealing temperature is increased. The DO3 ordered region in the α-Fe(Si) grain is spherical approximately, and its size increases as the annealing temperature increases. The size of the DO3 ordered region is 12.8 nm at the temperature of 570℃,which is close to that of the α-Fe(Si) grain. There is obvious change in the structure of the residual amorphous phase during annealing, and the nearest atomic distance and the short-range order of residual amorphous phase reach maximum and minimum at 530℃, respectively. The initial permeability of annealed Fe73.5 Cu1 W3Si13.5 B9 alloy is not only dependent on the size, volume fraction and Si content of the α-Fe(Si) phase but also related to the structure state of the residual amorphous phase.展开更多
文摘The direct observations of the atomic arrangements in both conventional furnace annealed and electric pulse rapid annealed Fe78B13Si9 amorphous alloy have been conducted by the lattice imaging technique in a higt resolution electron microscope. The results showed that the embrittlement of the alloy was related to the extent of atomic rearrangements during the annealing processes. The embrittlement of the alloy after 1hour conventional furnace annealing at about 270℃ is caused by the sufficient atomic rearrangements which are characterized by the growth of some bct Fe3B-like atomic short range ordering regions already existed in the as-quenched structure. Electric pulse rapid annealing can effectively retard the above-mentioned atomic rearrangements and thus restrain the embrittlement. The embrittlement only occurs when certain amount of bcc α-Fe nanocrystals are precipitated in the amorphous matrix during electric pulse rapid annealing.
文摘Ion beam sputtering profiling in combination with SIMS technique was employed to investigate the Al diffusion in Fe_(78)Si_0B_(13)amorphous alloy.Between 320 and 380℃,the diffusion coefficients vary from 2.43×10^(-22) to 2.01×10^(-21)m^2s^(-1),and an Arrhenius relationship was established as:D_0=2.02×10~_(12)exp(-1.17/kT)
文摘The thermal expansion along the longitudinal and transverse directions for amorphous Fe_(78)B_(13)Si_9 alloy prepared under various preparing conditions were investigated.The thermal expansion anisotropy appears in all specimens.The expansion along the longitudinal direction is less than that along the transverse direction.The cooling rate,the melt temperature before jet casting and the cycling temperature affect the thermal expansion coefficients and anisotropy.The amisotropy of thermal expansion originates from the orientation of atomic interaction force,the atomic oscillatory frequency and short range order structure or the directional arrangement of defects in the alloy.
文摘A new method was developed for preparing nanocrystalline alloy made of the identi- cal compositional Fe_(78)B_(13)Si_9 amorphous ribbon by suitable isothermal annealing.Its microstructure and some structure-sensitive properties.including thermal expansion,spe- cific heat,etc.,have been studied and measured.Comparative analysis of properties was also carried out with amorphous and coarse-grained crystalline alloys of same composi- tion,thus.it is believed that so novel differences in properties from usual materials would be made by the particular microstructure of short range disorder of the nanocrystalline alloy.
文摘The nanocrystalline structure of annealed Fe73.5 Cu1 W3Si13.5B9 alloy has been investigated by using the XRD and the TEM methods. The relation between the initial permeability and the microstructure of the annealed alloy has been discussed. The crystalline phase in annealed Fe73.5 Cu1 W3Si13.5B9 alloy is the α-Fe(Si) phase with DO3 superstructure. The volume fraction, Si content and degree of order of the αFe(Si) phase increase with increasing annealing temperature. In the temperature range of 490-570℃, the α-Fe(Si) phase has a size of 13 nm, and its grain number increases as the annealing temperature is increased. The DO3 ordered region in the α-Fe(Si) grain is spherical approximately, and its size increases as the annealing temperature increases. The size of the DO3 ordered region is 12.8 nm at the temperature of 570℃,which is close to that of the α-Fe(Si) grain. There is obvious change in the structure of the residual amorphous phase during annealing, and the nearest atomic distance and the short-range order of residual amorphous phase reach maximum and minimum at 530℃, respectively. The initial permeability of annealed Fe73.5 Cu1 W3Si13.5 B9 alloy is not only dependent on the size, volume fraction and Si content of the α-Fe(Si) phase but also related to the structure state of the residual amorphous phase.
