Abstract
High density powder metallurgy duplex stainless steels have been obtained by mixing water andgas atomised powders. AISI 434L water atomised ferritic powders were mixed with differentpercentages (up to 50%) of AISI 316L gas atomised powders. The mixtures were then compactedby uniaxial pressing and vacuum sintered at three temperatures. Physical and mechanicalproperties were measured, showing the positive influence of small size austenitic powders indensity and strength. Best materials were submitted to oxidation tests at 800 and 900°C. Massgains during high temperature exposure have been dramatically reduced by the addition of gasatomised powders. Characterisation of the scales through scanning electron microscopy andX-ray diffraction has shown that the mixtures mainly comprise chromia, although other oxideshave been detected.