Mechanical property enhancement of sintered Nd-Fe-B magnets by dual-scale regulation of microstructure

The brittleness of sintered Nd-Fe-B magnet limits its applications in high frequency and high vibration envi-ronments. In this study, rod-like Ti particles were applied for dual-scale microstructure regulation to improve the mechanical properties of sintered Nd-Fe-B magnets. The bending strength of Ti-added magnets increased from 403.47 to 631.98 MPa, which shows an increase of 56.6%. The intrinsic coercivity of the Ti-added magnet increased from 15.20 kOe to 17.52 kOe. The mechanical properties and intrinsic coercivity are significantly improved without reducing the remanence. The Ti particles reduced the grain size and favorably altered the alignment of the grains, and hence effectively reduced the stress concentration effect. Furthermore, Ti particles promoted the formation of nano amorphous phase in the grain boundary phase, which greatly improved the strength of the grain boundary phase. This study provides a theoretical basis for the preparation of sintered Nd-Fe-B magnets with excellent mechanical properties.