Evaluation of microstructure anisotropy on room and medium temperature ECAP deformed F138 steel

N. S. DE VINCENTIS; A. KLIAUGA; M. FERRANTE; M. C. AVALOS; H-G. BROKMEIER; R.E. BOLMARO

MATERIALS CHARACTERIZATION

ELSEVIER SCIENCE INC

Lugar: Amsterdam; Año: 2015

1044-5803

Themicrostructure developed during severe plastic deformation results in improvedmechanical propertiesbecause of the decrease in domain sizes and accumulation of defects, mainly dislocation arrays. Thecharacteristic deformation stages observed in low stacking fault energy (SFE) face centered cubic (FCC)materials are highly influenced by the development of the primary and secondary twinning that competewith dislocation glide. In this paper, a low SFE F138 stainless steel is deformed by equal channel angularpressing (ECAP) up to 4 passes at room temperature (RT) and at 300 °C to compare the grain refinementand twin boundary development with increasing deformation. Tensile tests were performed to determinethe deformation stages reached by the material before and after ECAP deformation, and the resultingmicrostructure was observed by TEM. X-ray diffraction and EBSD, average technique the first andlocal the second one, were used to quantify the microstructural changes, allowing the determination ofdiffraction domain sizes, dislocation and stacking fault densities and misorientation indices, which leadto a complete analysis of the deformation introduced in the material, with comparative correlationsbetween various microstructural parameters.