Anisotropic plastic deformation behavior of B2—ordered Fe1Al single crystals at room temperature

The tensile plastic deformation behavior of B2-ordered Fe3Al single crystals at room temperature was systematically investigated.The results show that the mechanical properties are strongly orientation dependent.The plastic elongation of crystals with orientation near[110]is as high as 42%.Slip trace analysis shows that although slip planes are found to change among {110},{112}and {123}with the change in orientations,the initial slip planes in all cases are{110},Five-stage work hardening curve including four linear stages and one parabolic stage in obtained;but not all stages are observed in the actual deformation of each crystal.In combination with investigations of dislocation substructure,it is found that deformations in stage Ⅰ-Ⅲ are corresponding to the motion of two-fold superdislocations.The higher work hardening rate of stage Ⅱ is mainly due to the stronger interactions between primary dislocations and secondary dislocations than those in stage Ⅲ.Deformation in stage Ⅳ involved is not only the motion of two-fold superdislocations but also the slip of dissociated superpartials with APB traps and the formation of APB tube,both of which are attributed to the hardening.Deformation in stage Ⅴ is comtrolled by the cross slip of dissociated superpartials.The dominated softening effect of cross slip reduces the hardening rate and leads to the formation of parabolic stage.