The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercool...The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312?nm, 11.2 in solid state, 0.301?nm, 10.932 in supercooled liquid region and 0.305?nm, 11.296 in liquid state. The crystal structure of Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy is consisted of several intermetallic compounds which are CuZr 2, Be 2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic compounds in a long range order.展开更多
The crystallization kinetics of amorphous Fe68.5Si13.5B9Cu1Nb3C5 (at. pct) melt-spun ribbons were studied by the DSC method in the mode of continuous heating. The apparent activation energy Ep1 and Ep2 (373.07±7....The crystallization kinetics of amorphous Fe68.5Si13.5B9Cu1Nb3C5 (at. pct) melt-spun ribbons were studied by the DSC method in the mode of continuous heating. The apparent activation energy Ep1 and Ep2 (373.07±7.92 and 518.75±21.35 kJ/mol, respectively) derived from the Kissinger plots were calculated by the peak temperatures Tp1, Tp2, which display a strong dependence on the heating rates. The crystallization behavior during isothermal annealing at 823 K for 1, 5, 10 h and 973 K for 5 h were investigated using XRD and TEM. The results show that crystallization behavior becomes completely different from that of FINEMET. It is not bcc α-Fe (Si) but metastable fcc γ-Fe (Si) that participates in the first crystallization step combining the appearance of Fe23B6 and Nb2B. Therefore, the addition of C promotes the combination of Fe and B. Fe3.5B is participated in the second step together with the disappearing of Fe23B6, which indicates that transition Fe23B6→Fe3.5B+Fe2B presumably happens. γ-Fe (Si) with peculiar stability cannot transform into nano-sized α-Fe (Si) crystals until the amorphous ribbons were annealed for 5 h at 973 K.展开更多
文摘The amorphous and crystal structures of Zr 41 Ti 14 Ni 10 Cu 12.5 Be 22.5 alloy have been analyzed with X ray diffractometer. The structures of bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in solid, supercooled liquid and liquid states are almost of the same structure. The RDFs (Radius Distribution Function), the first coordination number, the first coordination radius, the correlation radius and atom number of the cluster were calculated for bulk amorphous Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy in different states. The first coordination sphere radii and the first coordination numbers are 0.312?nm, 11.2 in solid state, 0.301?nm, 10.932 in supercooled liquid region and 0.305?nm, 11.296 in liquid state. The crystal structure of Zr 41 Ti 14 Ni 10 Cu 12.5 B 22.5 alloy is consisted of several intermetallic compounds which are CuZr 2, Be 2Zr, etc. The reason of formation glass for this alloy is that there is a larger resistance for atoms to rearrange and form intermetallic compounds in a long range order.
基金This work was supported by the National Natural Science Foundation of China under grant No.50271037.
文摘The crystallization kinetics of amorphous Fe68.5Si13.5B9Cu1Nb3C5 (at. pct) melt-spun ribbons were studied by the DSC method in the mode of continuous heating. The apparent activation energy Ep1 and Ep2 (373.07±7.92 and 518.75±21.35 kJ/mol, respectively) derived from the Kissinger plots were calculated by the peak temperatures Tp1, Tp2, which display a strong dependence on the heating rates. The crystallization behavior during isothermal annealing at 823 K for 1, 5, 10 h and 973 K for 5 h were investigated using XRD and TEM. The results show that crystallization behavior becomes completely different from that of FINEMET. It is not bcc α-Fe (Si) but metastable fcc γ-Fe (Si) that participates in the first crystallization step combining the appearance of Fe23B6 and Nb2B. Therefore, the addition of C promotes the combination of Fe and B. Fe3.5B is participated in the second step together with the disappearing of Fe23B6, which indicates that transition Fe23B6→Fe3.5B+Fe2B presumably happens. γ-Fe (Si) with peculiar stability cannot transform into nano-sized α-Fe (Si) crystals until the amorphous ribbons were annealed for 5 h at 973 K.
