Effect of Pulsed Magnetic Field on Spark Plasma Sintering of Iron-Based Powders

Iron-based powders were sintered by spark plasma sintering coupled with different pulsed magnetic field strength ranging from 0 to 3.93 MA.m(-1). The effects of pulsed magnetic field on the sintering behavior of the powders as well as the microstructure and mechanical properties of sintered alloys were investigated. The results showed that the sintering temperature field on the cross section of sample was more uniform via coupling a pulsed magnetic field. The density, hardness and bending strength of the alloy sintered by coupling an appropriate pulsed magnetic field, arose to 7.75 g.cm(-3), 55 HRC and 1235 MPa, respectively. There was no remarkable change of sintered density with a further increase of pulsed magnetic field strength, while the hardness and bending strength of sintered alloys adversely decreased. The roles of pulsed magnetic field coupled with electric field are explained to accelerate the diffusion and reaction of alloying elements by raising sintering temperature, facilitate powders rearrangement, intensify sparking among powders, improve the growth of sintering neck and the formation of new sintering neck, and reduce the sintering temperature gradient on cross section. [doi:10.2320/matertrans.M2010057]