Crystal plasticity theory during the 1950s and 1960s

Abstract

In the field of crystal plasticity, the two decades 1950–1969 were a time of great activity, in which the foundations were laid for our present understanding of the work-hardening of face-centred cubic metals in terms of dislocation mechanisms. Decisive developments were the ‘invention’ of the Frank–Read source, the recognition of the importance of the specific energy of stacking faults, and the (at least partial) resolution of the controversy between macroscopic stress–strain measurements, X-ray results, ferromagnetism and the study of slip lines and slip bands on the one hand, and the observation of dislocations by transmission electron microscopy of thin foils prepared from plastically deformed macroscopic specimens on the other hand. The understanding of the dislocation mechanisms dominant at very large plastic strains was and still is limited, however. It is argued that here a holistic approach based on concepts such as energy dissipation and self-organization is more promising than the mechanistic approach based on concepts successfully developed in the two decades covered in the paper.