Microstructure evolution of Ferritic ODS steel by a simple torsion test

These characteristics originate from microstructures consisting of fine grains and nano-oxide particles dispersed in high a number density. In particular, the grain size is a key structural factor affecting nearly all aspects of the physical, chemical, and mechanical behavior of metals. While many studies have been made on microstructure evolution for austenitic ODS steels, the microstructure evolution of ferritic ODS steels related to the deformation mechanism has not yet been clearly understood. This study investigates the microstructural evolution and microhardness of ferritic ODS steel during forward and reverse shear strain by using a torsion test. The microstructures were observed using electron backscatter diffraction (EBSD) and transmission electron microscopy (TEM). The microstructural evolution and microhardness of ferritic ODS steel during forward and reverse shear strain were investigated. Grain refinement with shear strain resulted in an increase in hardness. The change in shear strain path reduced the anisotropy, yet made the hardness value to higher owing to the formation of cell structures of dislocation entanglement inside the grain