ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The hydrogenation, disproportionation, desorption, recombination (HDDR) is known as a unique process through which a noncoercive cast Nd–Fe–B-type material can be easily converted into a coercive one. Although the conventional HDDR process generally leads to a powderlike material, a solid-HDDR material can be realized if the HDDR process is properly modified (solid-HDDR). In the present study, the change of mechanical strength (compressive strength) of the Nd–Fe–B-type material during the solid-HDDR has been investigated using a sintered magnet with composition Nd13.8Dy0.7Fe78.25Si0.15Mn0.6B6.5. It has been found that the low strength of the hydrided material was improved by the subsequent disproportionation. The restoration of the strength was explained by the eutectoidlike disproportionation structure containing fine neodymium hydride rod embedded in tough iron matrix. The high strength of disproportionated material was reduced radically in an earlier stage of recombination, and this was explained by the reduction of the disproportionated phase. The reduced strength was, however, recovered by further recombination, and this was explained by the fact that as the recombination continues the recombined grains become continuous and adhere together. The optimally HDDR processed material has a comparable or even higher strength with respect to the initial sintered material prior to the solid-HDDR. The present study suggested that the mechanical strength of Nd–Fe–B-type material could be retained even after the solid-HDDR. © 1998 American Institute of Physics.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.367542
