단순 전단변형에 의한 15Cr 산화물 분산강화 강의 미세조직 변화

Abstract

15Cr-1Mo base oxide dispersion strengthened (ODS) steel which is considered to be as a promising candidatefor high- temperature components in nuclear fusion and fission systems because of its excellent high temperaturestrength, corrosion and radiation resistance was fabricated by using mechanical alloying, hot isostatic pressing and hotrolling. Torsion tests were performed at room temperature, leading to two different shear strain routes in the forwardand reverse directions. In this study, microstructure evolution of the ODS steel during simple shearing was investigated. Fine grained microstructure and a cell structure of dislocation with low angle boundaries were characterized with shearstrain in the shear deformed region by electron backscattered diffraction (EBSD). Grain refinement with shear strainresulted in an increase in hardness. After the forward-reverse torsion, the hardness value was measured to be higherthan that of the forward torsion only with an identical shear strain amount, suggesting that new dislocation cell structuresinside the grain were generated, thus resulting in a larger strengthening of the steel.