High-strain-rate deformation: Mechanical behavior and deformation substructures induced

Abstract

The influence of increasing strain rate on the mechanical behavior and deformation substructures in metals and alloys that deform predominately by slip is very similar to that seen following quasi-static deformation at increasingly lower temperatures or due to a decrease in stacking-fault energy (γsf). Deformation at higher rates (a) produces more uniform dislocation distributions for the same amount of strain, (b) hinders the formation of discrete dislocation cells, (c) decreases cell size, and (d) increases misorientation, with more dislocations trapped within cell interiors. The suppression of thermally activated dislocation processes in this regime can lead to stresses high enough to activate and grow deformation twins even in high-stacking-fault-energy, face-centered-cubic metals. In this review, examples of the high-strain-rate mechanical behavior and the deformation substructure evolution observed in a range of materials following high and shock-loading strain rates are presented and compared with those seen following quasi-static-loading deformation paths. © Copyright ©2012 by Annual Reviews. All rights reserved.