Effect of order-disorder transition on magnetic properties of rapidly soldified high silicon-iron ribbons
The effect of ordering on the soft magnetic properties of 6.5% silicon-iron ribbons obtained by rapid solidification is studied. The atomic order cannot be prevented by the fast cooling. It is shown that isothermal aging at 700 degrees C induces a small decrease in coercive force and hysteresis losses, while aging at 500 degrees C induces an increase in these parameters. The magnetic evolutions are corroborated by Lorentz microscopy observations. The values obtained and the observations suggest a weak individual interaction, which may be due to local variation of exchange and anisotropy energy. >
Magnetic properties of 6.5 percent silicon-iron ribbon formed by a melt spinning technique
Silicon-iron alloys containing 6.5 percent silicon can be formed into ribbons by a melt spinning technique. The ribbons obtained were 10-40 μm in thickness, 1-2 mm in width, and 5-10 m in length, and after annealing all of them were remarkably flexible so as to be bent 180°. The as-quenched ribbons are crystalline and are not amorphous. Low loss is maintained for frequencies up to 50 kHz for 15-μm thick 6.5 percent silicon-iron ribbons. The values obtained for as-quenched ribbon were relative permeability \mu_{R} = 6000 , and loss per cycle W_{f}/f= 30 mJ/kg, measured at a maximum induction of 0.8 T and frequency of 50 kHz.
Electron Metallography of a Non‐Classical Order—Disorder Transition
Transmission electron metallography has been used to resolve the microstructural changes which occur during the D03⇄L20 transition in an Fe26.5at%Al alloy. The micrographs show evidence for a) long-range-order fluctuations near the critical temperature, b) local lowering of a critical temperature in the neighborhood of domain boundaries, and c) absence of a stable two-phase field separating the D03 and L20 phases. From these results it is concluded that the subject transition is not a classical (nucleation and growth) phase change. 
 
 
 
Transmissions-Elektronenmetallographie wurde zur Auflosung mikrostruktureller Anderungen, die wahrend des D03⇄L20−Ubergangs in einer Fe26,5At%Al-Legierung auftreten, verwendet. Die Mikrographien zeigen a) Fernordnungsfluktuationen in der Nahe der kritischen Temperatur, b) lokale Erniedrigung einer kritischen Temperatur in der Nachbarschaft von Domanengrenzen und c) die Abwesenheit eines stabilen Zwei-Phasenfeldes, das die D03− und L20−Phasen trennt. Aus diesen Ergebnissen wird geschlossen, das der untersuchte Ubergang keine klassische (Keimbildungs- und Wachstums-) Phasenanderung ist.