Microstructural Evolution of a Heterogeneous Austenitic Stainless Steel Processed by Equal Channel Angular Sheet Extrusion (ECASE)

MUÑOZ, JAIRO ALBERTO; TARTALINI, VANINA; RISSO, PABLO; ÁVALOS, MARTINA; BOLMARO, RAÚL

Capital Federal

Congreso; Congreso Internacional CIASEM 2019; 2019

SAMIC y SAM

Stainless steels stand out for their excellent properties such as corrosion resistance, high temperature resistance and good formability among others. From a mechanical point of view, austenitic stainless steels (ASS) are materials that attract attention due to their wide mechanical strength range that can be achieved mainly due to the deformation induced phase transformation phenomenon, from austenite fcc to martensite bcc. After ECASE processing, it was found that greater deformations were introduced around the sheet edges, while the middle area remained less affected by the deformation. The greater deformations at the edges caused a greater transformation from austenite to martensite, resulting in a heterogeneous structure along the sheet thickness. Tensile tests revealed that after the deformation process, the material increased its yield strength almost 3 times from 200MPa in its initial state to 600MPa. The tensile tests in different areas of the sheet thickness revealed a heterogeneous behavior with tougher and less ductile areas (greater amount of bcc martensite) and other more ductile but softer areas (greater amount of austenite). The main objective of this research is the study of mechanical and microstructural properties of a heterogeneous structure in an austenitic stainless steel deformed by ECASE maintaining a good strength-ductility ratio.