Solidification microstructure selection of the peritectic Nd-Fe-B alloys

Abstract

Bridgman directional solidification and laser remelting experiments were carried out on Nd11.76Fe82.36B5.88 and Nd 13.5Fe79.75B6.75 alloys. Microstructure evolutions along with solidification parameters (temperature gradient G, growth velocity V and initial alloy composition C 0) were investigated. A solidification microstructure selection map was established, based on the consideration of solidification characteristics of peritectic T1 phase. In Bridgman directional solidification experiments, with the increasing growth velocities, the morphology of T1 phase changed from plane front or faceted plane front to dendrites. In laser remelting experiments, a transition from primary γ-Fe dendrites to T1 dendrites was found. Theoretical predictions are in good agreement with experimental results. © 2007 Science In China Press.