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

MUÑOZ, J. A.; TARTALINI, V.; RISSO, P.; AVALOS, M.; BOLMARO, R. E.

MICROSCOPY & MICROANALYSIS

CAMBRIDGE UNIV PRESS

Año: 2020 vol. 26 p. 87 - 88

1431-9276

Stainless steels stand out for their excellent properties such as corrosion resistance, high temperatureresistance and good formability among others [1?4]. From a mechanical point of view, austeniticstainless steels 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 [5?7]. In this study, an austenitic stainless steel (≤0.03C; 18?20Cr; 69.9?74% Fe; ≤2Mn; 8?12Ni; ≤0.045P; ≤1Si; ≤0.03S (wt%)) in the form of Sheet (20 mm wide and 5 mm thick) was processed by 1 ECASE pass at room temperature using a matrix with an inner channel angle of Ф = 150 °   The microstructure characterization was carried out by electron backscattered diffraction (EBSD). 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. The heterogeneous structure obtained consists mainly of a more pronounced phase change in the sheet edges vicinity than the middle zone, as well as a greater Geometrically Necessary Dislocations (GND) density at the edges than the middle zone  For this reason, through mechanical tests and microstructural characterization, the ductility and strength contributions of each of these areas to the heterogeneous material was studied