Influence of dispersoids on the creep behavior of dispersion strengthened aluminum materials

Abstract

The creep behavior of a rapidly solidified Al-6.5%Fe-0.6%V-1.3%Si dispersion strengthened material containing 16 volume % of dispersoids has been studied by means of tensile tests at high temperatures from 483 to 821 K. The imposed strain rates ranged from 2.5∙10^-6 to 10^-2s^-1. The microstructure was very fine, consisting of submicron grains and small hard round-shaped dispersoids of about 54 nm. The creep behavior was characterized by high apparent stress exponents and high activation energies that are not accurately predicted by models from the literature. Therefore, a creep equation is developed to describe the creep behavior of the studied aluminum dispersion strengthened material and other materials with similar microstructures. The proposed equation is a generalization of conventional slip creep equations without the use of a threshold stress.