Effects of Coincident Site Lattice Grain Boundaries and Ordered Structures on Mechanical Properties of High Silicon Steel

The coincident site lattice (CSL) grain boundaries and ordered structures of high silicon steel are investigated through different warm rolling reductions. The results reveal that the plastic deformation ability of Fe-6.9 wt%Si warm-rolled sheet mainly depends on the total content of special n-ary sumation CSL boundaries and antiphase domain of ordered structures. With the increase of rolling reductions from 65% to 86%, the superdislocation glide behavior of warm-rolled sheets is changed into the single dislocation glide, as well as the fragmentation behavior of ordered structures at different rolling reductions causes a decrease in the sizes of antiphase domains. While the sharp and homogeneous distribution of gamma-orientation texture is beneficial to obtain a large fraction of n-ary sumation CSL boundaries that have great contribute to high resistance to the initiation and propagation of cracks. In the three-point bending tests, the values of fracture deflection improves from 3.5 mm to 12.1 mm, and the mixed fracture mode of inter-and trans-granular is transformed into quasi-cleavage fracture mode, which indicates the high rolling reduction is conducive to the improvement of plastic deformation ability.