The combined effect of B2 phase transfer and grain boundary character on mechanical properties of the Fe–6.5 wt% Si alloy was investigated. The microstructures and textures of the Fe–6.5 wt% Si alloy under four cooling modes were characterized by X-ray diffraction, transmission electron microscope, and electron backscattered diffraction. The results reveal that the maximum nano-hardness value (8.9 GPa) results from the two-step air-cooling sample, while for the two-step water-cooling sample, the minimum value (5.3 GPa) is achieved. The transformation of the B2 phase affected by the water-cooling process is a critical factor in obtaining the lower APB energy and eliminating the brittlenes. A large fraction of the coincidence site lattice boundaries that formed on the sheet experienced the two-step water-cooling process due to a uniform and sharp γ-fiber recrystallization texture comprising the {111} 〈110〉 and {111} 〈112〉 components, which enhances resistance to intercrystalline effect and improves mechanical properties in comparison with the two-step air-cooling process.

In the present work, the evolution of microstructure and mechanical properties of high-strength low-alloy D6AC steel containing the Ce element was synthetically investigated by means of electron backscatter diffraction, scanning electron microscope, Transmission electron microscope, and tensile and impact tests. The experimental results show that adding a certain amount of Ce into HSLA-D6AC steel can refine grains and martensite laths, as well as increase the fine VC precipitates, which not only enhance the strength of the steel but also improve the toughness and plasticity. Meanwhile, the morphology of martensite in HSLA-D6AC steel changes from twin martensite to dislocation martensite. It is found that after adding Ce, HSLA-D6AC steel exhibits a distinct necking stage in the tensile test, and the impact toughness value increases from 83 to 136 J. With the appearance of some more and deeper homogeneous dimples, the quasi-cleavage fracture transforms into a ductile fracture characterized by microvoid coalescence, demonstrating that HSLA-D6AC steel with the Ce element achieves excellent comprehensive mechanical properties.

Ordered phases and ductility of Fe–6.5 wt% Si magnetic material were investigated under different rolling temperatures, and the constitutive equation of the warm deformation was established. The results show that at high rolling temperature, accompanying with the appearance of some shallow dimples, the intergranular fracture can be transformed into the quasicleavage fracture, which makes the ductility of warm-rolled sheets greatly improved. In the 450–650 °C rolling temperature range, the antiphase domains (APDs) of warm-rolled sheets are cut, the superdislocation density increases greatly with decreasing warm rolling temperatures, resulting in a decrease in APD sizes during warm deformation. Meanwhile, more B2 and DO3 ordered phases occurring in the matrix improve the long range order parameters, thereby significantly reducing ductility of the alloy. The work softening of Fe–6.5 wt% Si alloy is attributed to a contribution combining the sizes of APDs with ordered phases.

As the core materials with excellent soft magnetic properties, Fe–6.5 wt% Si steel was fabricated by using the warm rolling process due to its extremely limited ductility and formability at room temperature. In this work, the effects of warm rolling reduction varying from 50% to 85% on the microstructure, texture, and magnetic properties of sheets were explored. The microstructure and texture evolution at the various processing steps were investigated in detail using optical microscopy, electron backscatter diffraction, and transmission electron microscopy. The results demonstrate that the finer recrystallization grains are accompanied with an increasing warm rolling reduction, and the final annealed sheets are characterized by strong α-fiber and γ-fiber textures. Accordingly, on the whole, as the increase of warm rolling reductions, the values of magnetic induction (B8, B50) in the final annealed sheets increase sharply up to a maximum value and then decrease to a certain value, and the values of iron loss (P15/50, P10/400) increase monotonically.