Effect of Processing Method on the Microstructure of Nd4.5Fe77B18.5 Magnetic Alloy

AbstractThe effects of processing method including arc-melted process, rapid solidification and laser crystallization on the microstructure of Nd4.5Fe77B18.5 alloy were investigated. The results showed that the microstructure of the arc-melted alloy was composed of Nd2Fe14B, Fe3B and α-Fe. The microstructure for the melt-spun alloy at the surface velocity of the wheel of 3m/s was similar to that of arc-melted one. However, the constituent phases were composed of Nd2Fe14B and Fe3B, and the α-Fe was suppressed for the melt-spun alloy at the surface velocity of the wheel of 5m/s. At the surface velocity of the wheel of 7m/s and 10m/s, the microstructures were composed of Fe3B and amorphous. Increasing cooling rate, the grain size decreased from micron to nanometer. The completely amorphous microstructure was obtained at the surface velocity of the wheel of 20m/s. The uniform Nd2Fe14B/Fe3B nanocomposites were obtained during the amorphous melt-spun crystallization by laser crystallization process. After laser crystallization at 400mm/min, the mean grain sizes of Nd2Fe14B and Fe3B reached 30nm and 20nm, respectively