Research on the mechanical properties of spark plasma sintering NdFeB sintered magnets

Conventional sintering technique and spark plasma sintering technique(SPS) have been used to prepare sintered NdFeB magnetic alloys of same composition. Mechanical properties and fracture behavior of the alloys were investigated. Microstructure and fracture morphology were observed by scanning electronic microscopy(SEM). Bending strength of alloys were tested and applied to evaluate the mechanical properties of alloys. The results show that the microstructure of SPS NdFeB is composed of fine and even matrix phase grains with average size of 5~ 8μm, as well as fine and separated Nd-rich phase, and its fracture morphology shows obvious tearing ridge and some cleavage face, whereas the microstructure of conventional sintered NdFeB is composed of coarse grains with size range from 10 to 20μm, its fracture morphology shows a typical inter-granular mode. The bending strength of SPS NdFeB and conventional sintered NdFeB are 402.25 and 278.97 MPa, respectively.