THE EFFECT OF THE COOLING RATE ON SOLIDIFICATION AND THE STRUCTURE OFTHE ND15FE78B7 ALLOY

The effect of the cooling rate on the microstructure and phase composi tion of magnetically hard Nd15Fe78B7 alloy is studied by metallography , X-ray diffraction, electron microprobe analysis, and magnetometry. T he increase in the cooling rate leads to the sequential suppression of peritectic reactions and to the departure of the alloy from equilibri um solidification paths. The sequence in which phases separate out in the process of solidification changes at a cooling rate of 10(4) K/min . The relationship is also established between the cooling rate, dendr ite parameter and relative content of various phase constituents in th e alloy.