Deformation twinning caused by warm rolling and secondary recrystallization in twin-roll strip casting Fe81Ga19 alloy

In the present work, the body-centered-cubic (BCC) Fe81Ga19 alloy was produced by twin-roll strip casting technology. The following warm rolling and slow heating heat treatment (from 800 ℃ to 1200 ℃, 20 ℃/h) was successfully applied to realize the secondary recrystallization of Goss grains. The magnetostrictive coefficient of the complete secondary recrystallization sheet was ~197 ppm. Deformation twins can be observed by electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) in warm-rolled sheets. An in-situ compression experiment showed that deformation twinning was related to grain orientation. The twins first formed in the grains with a higher Schmid factor and then appeared in the lower Schmid factor grains with the increase of deformation. Besides, deformation twinning can adjust the grain orientation and further activate dislocation slip. The unique Slip-Twinning-Shearing plastic deformation mechanism of BCC Fe-Ga alloy provides the possibility to overcome the intrinsic brittleness and produce sheets by rolling technology.