Directional solidification and characterization of binary Fe-Pr and Fe-Nd eutectic alloys

In this work, the directional solidification technique was employed in bina ry Fe-Pr and Fe-Nd eutectic alloys with compositions near to their respecti ve eutectic points. Solidifying the Fe-Pr and Fe-Nd hypereutectic alloys in a vertical Bridgman crystal growth unit, we were able to obtain the two eu tectic morphologies, one globular and other feathered, normally observed in as-cast samples, in a coarser form and sequentially displayed along the le ngth of the samples. The transition temperatures nearby to the eutectic poi nts were also determined using a Calvet type calorimeter. The phases compri sing the globular and feathered morphologies were determined as being, resp ectively, Fe17R2 and Fe2R (R=Pr or Nd), for both systems. These experiments also showed very clearly the peritectic formation of the Fe2R phases from the Fe17R2 and the liquids. Thermomagnetic measurements gave the Curie temp erature as being 44 degreesC for the Fe2Pr phase and 252 degreesC for the F e2Nd phase. (C) 2001 Elsevier Science B.V. All rights reserved.