Dislocation velocities in CuNi alloys determined by the stress pulse-etch pit technique and by slip line cinematography

Dislocation velocities are measured in Cu–(2 to 10%)Ni single crystals in the yield region at 300 K using both, the etch pit technique and high speed cinematography of slip bands. By both the methods velocities of dislocation groups and individual dislocations in groups are found to be (10 to 40) mm s−1 for screw and edge characters, if their motion is controlled by the dislocation solute atom interactions only, i.e. in the first stages of development of isolated slip bands. Later the average rate of growth of slip bands decreases considerably due to interactions between dislocations. The results indicate a stress exponent of the dislocation velocity of 5 to 11 at the macroscopic critical resolved shear stress.