Nd2Fe14B: (Nd1-x Dyx )2 Fe14B core-shell structure formation by hot press liquid phase sintering

The purpose of this project is to produce Nd rich core-Dy rich shell grain structure in liquid phase sintered alloys by consolidating Dy rich powder mixed with Nd_2 Fe_14 B powder. The technical barrier to producing the core-shell microstructure is that the Dy composition variations will homogenize during the consolidation process. This dissertation is based on the hypothesis that compositional homogenization of the core-shell structure can be minimized if consolidation occurs under applied pressure (hot press liquid phase sintering). The hypothesis is tested by comparing the homogenization of the Dy composition to the degree of consolidation with and without applied pressure. It is demonstrated that Nd rich core-Dy rich shell grain structure can be produced using the hot press approach. A simple linear model is used to identify the critical processing parameters involved in the successful development of the requisite core-shell structure.