Nd-Fe-B magnets mechanical properties improved

Image shows typical fracture pattern (red) in Nd-Fe-B sintered magnet (black: Nd-oxide phase)
Typical fracture pattern (red) in Nd-Fe-B sintered magnet (black: Nd-oxide phase)

CMI researchers at Ames Laboratory conducted the research for this highlight

Innovation
A microstructural modification was identified to enhance the mechanical properties in the Nd-Fe-B magnet while considering magnetic properties and chemical stability.

Main Achievements

  • Found that both Nd and Nd6Fe13Cu-type grain boundary phases enhance fracture strength of Nd-Fe-B magnets by up to 2.5 times.
  • Identified Nd6Fe13Cu-type as preferred option due to better chemical stability over Nd metal, while retaining ~1.5 times the strength of a baseline magnet.
  • This approach shows good promise and may even transition fracture mode from intergranular to trans- and inter-granular mixed mode.

Significance and Impact
Engineering grain boundary phases will enable enhancement of mechanical properties without sacrificing magnetic performance. 

Hub Goal Addressed
Increase speed of discovery and integration. 

line graph shows stress-strain curve of Nd-Fe-B magnet with different GBP.
Stress-strain curve of Nd-Fe-B magnet with different GBP.