PRIMARY CREEP AND ANELASTIC BEHAVIOR OF ALUMINUM AT LOW STRAINS AND TEMPERATURES BELOW 0-45T(M)

Using highly sensitive equipment for the measurement of small shear st ains up to 1.5 x 10(-4) and their variation with time, the form of the primary creep curves for aluminium at low stresses has been determine d. The extent and rate of recovery of these strains has also been meas ured to establish the pattern of anelastic behaviour, and best fit equ ations are presented. A unique activation enthalpy could not be identi fied for anelastic recovery, but a value for the activation enthalpy c omparable with grain boundary or dislocation pipe diffusion was derive d from primary creep when the strain exceeded 10(-5). The ratio of the anelastic recovery strain to the forward creep strain decreased logar ithmically with time over most of its range, but reached a limiting va lue that was dependent on the forward creep stain. (C) 1996 The Instit ute of Materials.