BAUSCHINGER EFFECT AND WORK-HARDENING IN ALUMINIUM SINGLE CRYSTALS DISPERSION-HARDENED WITH SILICON PARTICLES.

Abstract

The crystals aged to contain silicon particles showed a pronounced Bauschinger effect. The reverse flow curves (compression) after tension showed an initial region of rapid work-hardening, subsequently a region of nearly linear and low work-hardening and finally a region of a parabolic work-hardening. When the crystals with small particles (2R less than equivalent to 30 nm) were deformed by a small amount of strain in pre-straining, the reverse stress-strain curve showed a sharp convex curvature in the region of rapid work-hardening. The mean internal stress increased initially with prestrain until a critical strain, epsilon //c, and then appeared to saturate with increasing pre-strain. Particle size dependence is discussed in terms of plastic relaxation due to secondary dislocation generation as well as cross-slip of Orowan loops.