Fracture mode of sintered NdFeB alloy and microstructure of fracture surface

The sintered permanent magnets of Nd33Fe65.95B1.05 were prepared via smelting, powdering, forming, sintering and tempering process. The mode and microstructure of the fracture surface were researched by SEM and metallographic microscope. It was showed that the fracture surfaces of the ingot are intergranuler fracture for its big brittleness and there are many Nd-rich phases at fracture surface but Nd2Fe14B phases are relatively integrated. The fracture mode of sintered NdFeB magnets is intergranuler fracture and transgranular fracture because there are lots of defects in magnets, however, their fracture mode is primarily intergranuler fracture. There are two factors accounting to the facture of sintered NdFeB magnets. The extrinsic factor is that there are a good deal of defects, such as h