The microstructural picture of deformation with reference to Al-, Mg- and Ti-alloys

The microstructural picture of inelastic deformation by motion of dislocations is outlined and the modeling of deformation kinetics and dislocation structure evolution is briefly reviewed. The steady state properties can be captured by modeling homogeneous dislocation activity, while transient deformation requires consideration of dislocation cell/subgrain structures evolving from the heterogeneous component of dislocation activity. The effective stress concept, on which the modeling of dislocation glide is based, is supported by results of stress reduction tests. When plotted as function of shear modulus normalized stress, the available data for characteristic dislocation spacings of Al-alloys and normalized inelastic strain rate of Al-alloys, die-cast Mg-Al-alloys and Ti-alloys yield essentially similar master curves, consistent with the dislocation model. The rather sharp transition between the dislocation structures with and without clouds of solutes is a prominent feature in deformation of the single-phase alloys. (author)