The evolution of cold-rolled deformation microstructure of {0 0 1}〈1 1 0〉 grains in Ta–7.5 wt%W alloy foils

The deformation structure of {0 0 1}〈1 1 0〉 grains in cold-rolled Ta–7.5 wt%W alloy foils has been investigated by transmission electron microscopy (TEM) and electron backscattering diffraction (EBSD). The results show that there are two kinds of {0 0 1}〈1 1 0〉 grains formed during the cold-rolled deformation process. Type A grains are surrounded by α-fiber, while type B grains are surrounded by γ-fiber. Dislocation analysis reveals a continuous evolution of dislocation substructures from dislocation arrays, to high dense dislocation walls, and to microbands in type A grains, while in type B grains from dislocation mesh to dislocation cells as a function of plastic strain. By both the analysis of EBSD and TEM, a new deformation mode in type A grains is developed.

► By the analysis of TEM and EBSD, there are two types of {0 0 1}〈1 1 0〉 grains formed during cold-rolled deformation with different surroundings. ► The evolution of deformation structure in type A and B grains is different. ► Dislocation analysis reveals a continuous evolution of the dislocation substructures from dislocation arrays, to high dense dislocation walls, and to microbands in type A grains, while in type B grains from dislocation mesh to dislocation cells. ► Meanwhile, a deformation mode is developed in grain A.