Architectured duplex stainless steels micro-composite: Elaboration and microstructure characterization

Abstract In this work we propose a top-down strategy in which an austenitic stainless steel (type AISI 316L) and a ferritic stainless steel (type AISI 430LNb) are mechanically alloyed by Severe Plastic Deformation (SPD) to elaborate an architectured duplex stainless steel. This proposed strategy serves two main objectives: i) enhancing the properties by microstructure refinement down to sub-micron scale, and ii) elaborating a model material for understanding the behavior of Duplex Stainless Steel (DSS) obtained by the conventional metallurgical methods. The Accumulative Drawing and re-Bundling (ADB) technique has been successfully implemented for these specific materials, allowing to obtain multi-scale micro-composites of 316L/430LNb steels. The limits of this process in terms of microstructure refinement, have been identified as due to the complete regression of the micro-scale austenitic phase during annealing.