Source initiation and obstacles to dislocation motion in Cu-1% Si single crystals

Abstract

The factors controlling initial dislocation mobility and the obstacles to plastic flow in stage I hardening for Cu-1% Si crystals of several orientations were studied by correlating the results of high-resolution strain measurements with etch-pit observations of the primary and forest dislocation structures of the same samples. The micro-yield stress (MYS), defined here as the stress required to produce a permanent plastic strain of ⋍ 2 × 10⁻⁷, was measured as a function of temperature, dislocation structure and solute distribution. It was concluded that the temperature dependence observed in the MYS, which was the same as that observed here for the flow stress, was caused by the dynamic interaction of the mobile primaries with the random solutes.