Analysis of the interface and mechanical properties of field-assisted sintered duplex stainless steels

The development of duplex stainless steels produced by powder metallurgy represents an interesting alternative to conventional fabrication routes, since typical routes imply a strict control of composition and temperature during the processing path in order to avoid undesirable brittle phases. This work proposes a sintering route, designated as field-assisted hot pressing technique, in which an alternating current is applied to consolidate duplex stainless steels with different initial austenite percentages, always higher than ferrite. In all the cases, a thin and hard planar interface composed by two different microconstituents is generated between austenite and ferrite, growing inside the ferritic phase. The good mechanical properties achieved by these field-assisted sintered duplex stainless steels, in terms of nanohardness, elastic modulus, yield strength, ultimate tensile stress and ductility, establish these steels as promising candidates to be introduced in the market.