Effect of die-upset level on the mechanical properties and microstructure of Nd-Fe-B magnets prepared by spark plasma sintering

► Mechanical properties and microstructure of Nd-Fe-B magnets produced at various die-upset levels have been investigated. ► Analyzed the reasons for the variations in the magnetic and mechanical properties of die-upset Nd-Fe-B magnets in detail. ► Remanence (Br) and maximum energy product (BH)max of Nd-Fe-B magnets increase linearly with the increase in die-upset level. ► Intrinsic coercivity of Nd-Fe-B magnets first increases, reaches maximum at the die-upset level of 40% and then decreases.