Creep tests were conducted on an Al-6092 alloy reinforced with 25 vol pct SiC particulates and on an unreinforced Al-6092
matrix alloy. Both materials exhibit creep behavior indicating the presence of a threshold stress and both have a true stress
exponent of 3, but with meaured activation energies for creep of ∼135 and ∼230 kJ mol
−1 in the unreinforced and reinforced materials, respectively. By incorporating a temperature-dependent load transfer into the
analysis, it is shown that the activation energy for the composite is reduced to ∼130 kJ mol
−1. Both materials therefore exhibit creep behavior consistent with viscous glide and the dragging of Mg solute atmospheres,
and in addition the results for the composite are consistent with the proposal that the creep of metal matrix composites divides
into two classes depending upon the rate-controlling process in the matrix alloys.