Effect of particle size and sintering temperature on densification during coupled multifield-activated microforming

In this paper, a novel sintering method is introduced for the forming of microcomponents in which the loose powders were loaded directly into the die, sintered with an external electric field, a thermal field, and an external stress field (called coupled multifields activation), where the fields were generated by a Gleeble thermal simulation instrument. Two kinds of 316L stainless steel powders of different particle sizes (20 and 70 μm) with no binder were sintered with microforming using a multifield coupling method. For particle size of 20 μm, a nearly fully densified microsintered compact (relative density is 99.2%) was manufactured at a relatively low sintering temperature (900 °C) and within a relatively short sintering time (4 min). The fluctuated temperature–time curve reveals that the rapid mass transfer of liquid phase is the dominant densification mechanism in the compacts with a starting particle size of 20 μm.