A quasi-in-situ EBSD study on the formation and development of η-fiber in 0.15 mm ultra-thin Fe-4.5 wt. % Si sheet

Texture evolution of 0.15 mm ultra-thin Fe-4.5 wt. % Si sheet with strong η-fiber produced by two-stage rolling and final annealing was investigated using ex-situ and quasi-in situ electron backscatter diffraction (EBSD). The Goss grain of the hot-rolled plate was rotated to γ-fiber (<111>//ND) dominated by {111}<112> during one stage of moderate warm rolling reduction and then formed strong Goss after intermediate annealing. When the rolling reduction was slightly increased, the annealed strong Goss rotated to near {111}<112> and then formed strong {120}<001> after final annealing. The quasi-in-situ EBSD characterization of the intermediate and final recrystallization process indicated that the recrystallized Goss, {120}<001> and {111}<112> grains were nucleated and grown within the shear bands of deformed {111}<112>, near {111}<112>({223}<362>), and {111}<110> matrices respectively. The recrystallized strong η-fiber textures dominated by {120}<001> were dependent on the coarser Goss grains and suitable rolling reduction and could remain unchanged after considerable grain growth. The 0.15 mm specimen with superior magnetic properties and high strength achieved an iron loss ( P _10/400 = 7.82 W/kg) improvement of 17 %, magnetic induction ( B ₅₀ = 1.65 T) improvement of 0.04 T, and yield strength (474 MPa) improvement of 61 MPa compared to commercial products with the same thickness.