Sintering transformations in mixtures of austenitic and ferritic stainless steel powders

The microstructural transformations and the dimensional evolution of green specimens obtained bypressing mixtures of austenitic and ferritic stainless steel powders have been investigated by sintering at 1120 and 1240 C. Dilatometry experiments show that the linear shrinkage is influenced by the amount of ferritic powder. Moreover, during sintering Ni diffuses into the ferritic grains causing austenite destabilisation and the formation of a mixed constituent, whose constitution has been investigated by means of EDXS and interpreted on the basis of the Schaeffler diagram. Sigma phase also forms during sintering of the duplex mixtures.