抄録
The effect of repeated transformation on sintering rate of iron powder compact has been investigated. Iron powder compacts were sintered under small compressive load by cycling temperatures from 25°C below to 25°C above the a ?? γ transformation temperature of iron (910°C), with various lengths of cycle and loads. The sintering rate was markedly accelerated by repeated transformation during sintering, compared with isothermal sintering. The shrinkage of compact in this repeated transformation sintering was dependent on the number of cycles, and the relationship between the shrinkage by transformation and the number of cycles was represented by a formula
S=AN
where S was the shrinkage of compact, N, the number of cycles, and A, a constant. It was concluded that the acceleration of sintering rate was due to the enhanced pore elimination by the transformation softening, that is, superplasticity occurred during the α ?? γ transformation.
