Characteristic Twin Formation in Body-centered Cubic Fe-Ga Alloy Single Crystals with Different Orientations

Tensile tests and electron backscatter diffraction (EBSD) measurements were performed to understand the microscopic processes in the plastic deformation of Fe-17-at%-Ga alloy single crystals with a bodycentered cubic (BCC) structure. Samples close to the [001], [012], and [011] orientations for the tensile directions were cut from the alloy single crystal grown by the Czochralski method. They were plastically deformed at room temperature. The surface morphologies and microstructures of the deformed samples were characterized using an EBSD instrument attached to a scanning electron microscope. The mechanical properties such as elasticity and flow stress depended on the crystal orientation. Slip by dislocation glide was dominant in the tensile deformation in the [011]-oriented sample. Coarse planar deformation twins were observed in the [001]-oriented sample by plastic deformation. Thin deformation twins and slips were observed in the [012]-oriented sample. This implies that deformation twins have an important role in the plastic deformation of alloys. Although the addition of Ga induces solid solution hardening of iron-based alloys, the characteristic microscopic processes in the plastic deformations of the present alloys are similar to those in the plastic deformations of BCC iron and its alloys.