Effect of Stress on Creep at High Temperatures

Abstract
Experimental investigations on pure aluminum and its dilute solid-solution alloys revealed that the high-temperature creep rate ϵ̇ is related to the stress σ by ϵ̇ ∼ σn for low stresses and ϵ̇ ∼ eBσ for high stresses where n and B are constants independent of the creep strain and temperature. According to a preliminary dislocation-climb model for high-temperature creep, the activation energy for creep is that for self-diffusion, the effect of stress on the creep rate depends on the number of active Frank-Read sources, and the rate of climb depends on the structure as determined by the pattern of climbing dislocations. Many of the experimental observations on high-temperature creep can be accounted for by this model.