AMORPHOUS PHASE SEPARATION IN RAPIDLY QUENCHED Fe-Cr-MO-Si-B ALLOYS
快淬Fe—Cr—Mo—Si—B非晶合金中的相分离

A comprehensive examination was made on the structures and properties of Fe65Cr18Mo2Si1B14 and Fe62Crl8Mo2Si1B17 single-roll quenched ribbons. TEM revealed par-ticle-like amorphous second phase with size of tens of nanometer distributed in amorphous matrix, amount of which increased with boron concentration. Correspondingly, magnetic analysis and M6ssbauer spectrum indicated that the ribbons were composed of phases with different magnetic properties. A small amount of magnetic phase was detected to be dispersed in paramagnetic matrix and has high coercive force as single-domain particle. The quenched ribbons were brittle before annealing. A conclusion can be drawn that the boron segregation in eariy undercooled liquid during quenching results in the formation of amophous second phase, which brittlized the quenched ribbons.