Abstract
Pressure sintering was carried out with atomized iron powder in graphite die at 600°C to 1150°C under the pressure of 50 to 550 kg/cm2. The densification behavior of the powder compact and the microstructure of the sintered body were investigated.
Under a constant pressure, maximum density was obtained by sintering at 850° or 900°C. When sintered at 900°C under 550 kg/cm2, density reached about 7.81 g/cm3, the highest value attained in this investigation. As the pressure increased, the temperature at which densification started decreased and the density increased. Carburization was observed in the surface part of the compact when sintered above 950°C.
In the early stage of pressure-sintering, plastic deformation of the powder particles was thought to be a predominant densification mechanism, and from the densification behavior, the yield stress values of the iron particles were estimated at the temperature range from 600°C to 900°C. Diffusion mechanisms seemed to become operative in the later stage.
