Growth kinetics in undercooled Nd–Fe–B alloys with carbon and Ti or Mo additions

Abstract The growth kinetics of stoichiometric Nd–Fe–B alloys with carbon and Ti or Mo additions have been investigated with the electromagnetic levitation technique. The growth velocity of the Nd2Fe14B (Φ) phase was measured in situ using a two-colour pyrometer and a fast responding photodiode. A strong reduction of the growth velocity of the Φ-phase in the Nd–Fe–B–Ti(Mo)–C was observed compared to the addition-less Nd–Fe–B alloy. Moreover, the alloying additions limit the undercooling range due to increased nucleation tendency. Microstructure investigations showed a remarkable grain refinement compared to the grain size of the stoichiometric Nd–Fe–B compound without alloying additions.