DISLOCATION CLIMB THEORIES OF CREEP AND SUPERPLASTICITY

Various dislocation theories of high temperature deformation are derived from two basic equations, the general equation of recovery creep which relates the steady-state creep rate to the rates of recovery and strain hardening, and the equation describing the loss rate of dislocations by climb. Normal, stress-sensitive creep occurs when glide dislocations are blocked by intragranular obstacles or by interaction with other glide dislocations. Superplastic creep which is stress-insensitive, is predicted when the grain boundaries act as sources, obstacles and sinks for dislocations. However, a more detailed examination of the creep behavior predicted by the theories shows that while recovery theories are good for normal creep, they are unsatisfactory for superplastic creep. © 1969.