Directional solidification experiments were performed on peritectic Nd13.5 Fe79.75 B6.75 alloy with temperature gradient of 180 K/cm and 250-360 K/cm obtained from total melting and zone melting

respectively

at pulling velocity ranging from 5 to 500μm/s to investigate the effects on microstructure and phase constituent in the alloy.The results indicate that the microstructure of the alloy is composed of primary α-Fe dendrites

peritectic Nd2Fe14B phase and minor Nd-rich phase.The volumetric fraction of ferromagnetic Nd2Fe14B phase is firstly increased and then decreased with rising the pulling velocity

and is improved with increasing temperature gradient.Grown at 50μm/s

the volumetric fraction of ferromagnetic Nd2Fe14 B phase reaches up to 90% in the zone melting specimens（given a temperature gradient at 300 K/cm）

which is about 30% higher than that in the total melting specimens（given a temperature gradient at 180 K/cm）.