Abstract
Creep tests on Al-5.5 at.-% Mg solid solution alloy show that the stress exponent n increases with increasing stress from 3.1 to 5.5. It is demonstrated that the transition to n approximate to 5.5 is not consistent either with normal power law breakdown or with a transition to a region of viscous glide controlled by pipe diffusion, but the results are in good agreement with a breakdown of the dislocations from their solute atmospheres. The activation energies for creep at low and high stresses are 136 and 170 kJ mol(-1) respectively.