MICROPROCESSES OF THE DEFORMATION OF NIAL SINGLE-CRYSTALS

NiAl single crystals were deformed in soft orientations inside a high- voltage electron microscope. At room temperature, dislocations with [1 00] Burgers vectors move on {100}, {110} and {210} planes and bow out between jogs. The shape of the bowing is determined by anisotropic lin e tension. The local effective stress calculated from the bowing is so mewhat smaller than the resolved shear stress quoted in the literature . Viscous motion between the stable positions hints at the additional action of the Peierls mechanism. Above about 400 degrees C, the disloc ation motion is smooth. It is suggested that it is controlled by diffu sion processes. (C) 1997 Elsevier Science S.A.