2024 年 63 巻 1 号 p. 1-7
Pure coppers and Cu–30 mass% Zn (Cu–Zn) alloys were tensile–deformed at room temperature and 573 K. Dislocation multiplications and dislocation motions during the tensile deformations were evaluated by neutron diffraction line–profile analysis. The dislocation density of the pure copper specimen during the deformation at 573 K was smaller than that during the room temperature deformation. On the other hand, the Cu–Zn alloys showed comparable dislocation multiplication at room temperature and 573 K. The crystallite sizes determined from the line–profile analysis suggested that the crystallites of the pure copper specimen became finer with increasing dislocation density, while crystallite was not formed in the Cu–Zn alloy specimen deformed at 573 K. In addition, in the Cu–Zn alloys, although the dislocation density at 573 K was comparable with that at room temperature, the texture evolved by dislocation motion was weakened at 573 K. Those suggests that dislocation motions are suppressed in Cu–Zn alloys. Transmission electron microscopy observations confirmed that completely different dislocation substructures were formed in the deformed Cu–Zn alloy at room temperature and at 573 K. The dislocation substructure formed by the room–temperature deformation was a Taylor lattice in which dislocations accumulate on planar slip planes, whereas in the 573 K deformation, the dislocations are randomly distributed in a wavy form and do not form tangle. The mobility of dislocations is reduced by the interaction between solid solution elements and dislocations in the Cu–Zn alloys at 573 K.
