Dislocation structures for octahedral slip in Ni3(Al, Ti) single crystals at elevated temperatures

Dislocation structures for the octahedral (111) slip system in Ni3(Al, Ti) single crystals deformed at temperatures above the yield stress peak were investigated as a function of temperature using TEM. As temperature increases, [101] edge dislocations become more predominant. Dislocations of screw character are in the almost complete Kear-Wilsdorf locked configuration while those of edge character are climb-dissociated on the (101) plane perpendicular to the (111) glide plane. It is suggested that the high-temperature deformation by the octahedral {111} slip in Ni3(Al, Ti) single crystals is controlled by the non-conservative motion of [101] edge dislocations connected with APB.