A review on spark plasma sintering of duplex stainless steels

Duplex stainless steels contain ferrite and austenite phases in balanced proportions. They exhibit good corrosion resistance in numerous environments and are resistant to pitting corrosion and stress corrosion cracking. DSS are employed in the process industries due to their ability to withstand erosive and aggressive environments and high pressure. Characteristic strength of DSS is twice that of the austenitic stainless steel. They are difficult to machine due to high toughness and low thermal conductivity. Conventional methods deteriorate machined surface and irregular wear that creates a negative impact on the efficacy of the material and productivity. The powder metallurgy is a prominent solution to produce DSS and is possible to control the chemical and phase composition, by eliminating number of difficulties present during the production of DSS by conventional methods. SPS is an advanced sintering technique used to fabricate poorly sinterable materials. SPS has a major advantage in the processing of high temperature materials with poor deformability. The ultra-fine grain structure obtained by SPS allows increase of strength and hardness in various stainless steel grades. In this review, nano structured DSS powders of composition Fe-25Cr-7Ni (wt. %) were prepared by dual drive planetary ball mill. The nano structured DSS powders consolidated by SPS technique were studied and characterized by X-Ray diffraction while morphology of DSS powders were studied by Scanning Electron Microscope.